Percutaneous spinal implants and methods

ABSTRACT

An apparatus includes a support member and a retention member. The support member has at least a portion configured to be disposed between a first spinous process and a second spinous process. The retention member is movably coupled to an end portion of the support member. The retention member is configured to displace a bodily tissue. The retention member is configured to move relative to the support member from a first position to a second position. The retention member is configured to limit movement of the support member along the longitudinal axis and relative to the first spinous process and the second spinous process when in the second position.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and is a continuation-in-part ofU.S. patent application Ser. No. 11/356,302, entitled “PercutaneousSpinal Implants and Methods,” filed Feb. 17, 2006, which claims priorityto U.S. Provisional Application Ser. No. 60/695,836, entitled“Percutaneous Spinal Implants and Methods,” filed Jul. 1, 2005, andwhich is a continuation-in-part of U.S. patent application Ser. No.11/252,880, entitled “Percutaneous Spinal Implants and Methods,” filedOct. 19, 2005, which is a continuation-in-part of U.S. patentapplication Ser. No. 11/059,526, entitled “Apparatus and Method forTreatment of Spinal Conditions,” filed Feb. 17, 2005, and which claimspriority to U.S. Provisional Application Ser. No. 60/695,836, entitled“Percutaneous Spinal Implants and Methods,” filed Jul. 1, 2005. Each ofthe above-identified applications is incorporated herein by reference inits entirety.

This application also claims priority to and is a continuation-in-partof U.S. patent application Ser. No. 11/356,301, entitled “PercutaneousSpinal Implants and Methods,” filed Feb. 17, 2006, which claims priorityto U.S. Provisional Application Ser. No. 60/695,836, entitled“Percutaneous Spinal Implants and Methods,” filed Jul. 1, 2005, andwhich is a continuation-in-part of U.S. patent application Ser. Nos.11/252,879 and 11/252,880, each entitled “Percutaneous Spinal Implantsand Methods,” and filed October 19, each of which is acontinuation-in-part of U.S. patent application Ser. No. 11/059,526,entitled “Apparatus and Method for Treatment of Spinal Conditions,”filed Feb. 17, 2005. Each of the above-identified applications isincorporated herein by reference in its entirety.

This application also claims priority to and is a continuation-in-partof U.S. patent application Ser. No. 11/693,496 entitled “PercutaneousSpinal Implants and Methods,” filed Mar. 29, 2007, which is acontinuation-in-part of U.S. patent application Ser. No. 11/454,153,entitled “Percutaneous Spinal Implants and Methods,” filed Jun. 16,2006, which is a continuation-in-part of International PatentApplication No. PCT/US2006/005580, entitled “Percutaneous SpinalImplants and Methods,” filed Feb. 17, 2006, and which is acontinuation-in-part of U.S. patent application Ser. No. 11/059,526,entitled “Apparatus and Method for Treatment of Spinal Conditions,”filed Feb. 17, 2005, and which is a continuation-in-part of U.S. patentapplication Ser. No. 11/252,879, entitled “Percutaneous Spinal Implantsand Methods,” filed Oct. 19, 2005, which claims priority to U.S.Provisional Application Ser. No. 60/695,836, entitled “PercutaneousSpinal Implants and Methods,” filed Jul. 1, 2005, and which is acontinuation-in-part of U.S. patent application Ser. No. 11/252,880,entitled “Percutaneous Spinal Implants and Methods,” filed Oct. 19,2005, which claims priority to U.S. Provisional Application Ser. No.60/695,836, entitled “Percutaneous Spinal Implants and Methods,” filedJul. 1, 2005. Each of the above-identified applications is incorporatedherein by reference in its entirety.

This application is related to U.S. patent application Attorney DocketNos. KYPH-001/22US-305363-2140, KYPH-001/23US-305363-2139 andKYPH-001/24US-305363-2163 each entitled “Percutaneous Spinal Implantsand Methods,” filed on the same date, each of which is incorporatedherein by reference in their entirety.

BACKGROUND

The invention relates generally to the treatment of spinal conditions,and more particularly, to the treatment of spinal compression usingpercutaneous spinal implants for implantation between adjacent spinousprocesses.

A back condition that impacts many individuals is spinal stenosis.Spinal stenosis is a progressive narrowing of the spinal canal thatcauses compression of the spinal cord. Each vertebra in the spinalcolumn has an opening that extends through it. The openings are alignedvertically to form the spinal canal. The spinal cord runs through thespinal canal. As the spinal canal narrows, the spinal cord and nerveroots extending from the spinal cord and between adjacent vertebrae arecompressed and may become inflamed. Spinal stenosis can cause pain,weakness, numbness, burning sensations, tingling, and in particularlysevere cases, may cause loss of bladder or bowel function, or paralysis.The legs, calves and buttocks are most commonly affected by spinalstenosis, however, the shoulders and arms may also be affected.

Mild cases of spinal stenosis may be treated with rest or restrictedactivity, non-steroidal anti-inflammatory drugs (e.g., aspirin),corticosteroid injections (epidural steroids), and/or physical therapy.Some patients find that bending forward, sitting or lying down may helprelieve the pain. This may be due to bending forward creates morevertebral space, which may temporarily relieve nerve compression.Because spinal stenosis is a progressive disease, the source of pressuremay have to be surgically corrected (decompressive laminectomy) as thepatient has increasing pain. The surgical procedure can remove bone andother tissues that have impinged upon the spinal canal or put pressureon the spinal cord. Two adjacent vertebrae may also be fused during thesurgical procedure to prevent an area of instability, improper alignmentor slippage, such as that caused by spondylolisthesis. Surgicaldecompression can relieve pressure on the spinal cord or spinal nerve bywidening the spinal canal to create more space. This procedure requiresthat the patient be given a general anesthesia as an incision is made inthe patient to access the spine to remove the areas that arecontributing to the pressure. This procedure, however, may result inblood loss and an increased chance of significant complications, andusually results in an extended hospital stay.

Minimally-invasive procedures have been developed to provide access tothe space between adjacent spinous processes such that major surgery isnot required. Such known procedures, however, may not be suitable inconditions where the spinous processes are severely compressed.Moreover, such procedures typically involve large or multiple incisions.

Thus, a need exists for improvements in the treatment of spinalconditions such as spinal stenosis.

SUMMARY OF THE INVENTION

Medical devices and related methods for the treatment of spinalconditions are described herein. In some embodiments, an apparatusincludes a support member and a retention member. The support member hasat least a portion configured to be disposed between a first spinousprocess and a second spinous process. The retention member is movablycoupled to an end portion of the support member. The retention member isconfigured to displace a bodily tissue. The retention member isconfigured to move relative to the support member from a first positionto a second position. The retention member is configured to limitmovement of the support member along a longitudinal axis of the supportmember and relative to the first spinous process and the second spinousprocess when in the second position. In some embodiments, for example,the retention member and a portion of the support member collectivelyform a portion of a saddle configured to receive a portion of the firstspinous process when the retention member is in the second position.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of a posterior view of a medicaldevice according to an embodiment of the invention in a firstconfiguration adjacent two adjacent spinous processes.

FIG. 2 is a schematic illustration of a posterior view of a medicaldevice according to an embodiment of the invention in a secondconfiguration adjacent two adjacent spinous processes.

FIG. 3 is a schematic illustration of a deforming element according toan embodiment of the invention in a first configuration.

FIG. 4 is a schematic illustration of a side view of the expandingelement illustrated in FIG. 3.

FIG. 5 is a side view of a medical device according to an embodiment ofthe invention in a first configuration.

FIG. 6 is a side view of the medical device illustrated in FIG. 5 in asecond configuration.

FIG. 7 is a perspective view of a medical device according to anembodiment of the invention in a first configuration.

FIG. 8 is a posterior view of a medical device according to anembodiment of the invention, a portion of which is in a secondconfiguration.

FIG. 9 is a posterior view of the medical device illustrated in FIG. 7fully deployed in the second configuration.

FIG. 10 is a front plan view of the medical device illustrated in FIG. 7in the second configuration.

FIG. 11 is a perspective view of an implant expansion device accordingto an embodiment of the invention.

FIG. 12 is an alternative perspective view of the implant expansiondevice illustrated in FIG. 11.

FIG. 13 is a perspective view of a portion of the implant expansiondevice illustrated in FIG. 11.

FIG. 14 is a cross-sectional view of a portion of the device illustratedin FIG. 11, taken along line A-A in FIG. 11.

FIG. 15 is a cross-sectional view of a portion of the device illustratedin FIG. 11 in a first configuration, taken along line B-B in FIG. 11.

FIG. 16 is a cross-sectional view of a portion of the device illustratedin FIG. 11 in a second configuration, taken along line C-C in FIG. 11.

FIG. 17 is a side perspective view of an implant according to anembodiment of the invention shown in a collapsed configuration.

FIG. 18 is a cross-sectional view of the implant of FIG. 17 taken alongline 18-18.

FIG. 19 is a side perspective view of the implant of FIG. 17 shown in anexpanded configuration.

FIG. 20 is a rear perspective view of the implant of FIG. 17 shown in acollapsed configuration.

FIG. 21 is cross-sectional view of the implant of FIG. 17 shown in acollapsed configuration taken along line 21-21.

FIG. 22 is a rear perspective view of an implant according to anembodiment of the invention shown in a collapsed configuration.

FIG. 23 is a cross-sectional view of the implant of FIG. 22 shown in acollapsed configuration.

FIG. 24 is a perspective view of the implant of FIG. 22 in a collapsedconfiguration disposed on an expansion tool according to an embodimentof the invention.

FIG. 25 is a perspective view of the implant and the expansion tool ofFIG. 24 taken along region 25.

FIG. 26 is a side cross-sectional view of the implant and the expansiontool of FIG. 24.

FIG. 27 is a side cross-sectional view of the implant and the expansiontool as shown in FIG. 26 taken along region 27.

FIG. 28 is a perspective view of the implant of FIG. 22 in an expandedconfiguration disposed on an expansion tool according to an embodimentof the invention.

FIG. 29 is a perspective view of the implant and the expansion tool ofFIG. 28 taken along region 29.

FIG. 30 is a side cross-sectional view of the implant and the expansiontool of FIG. 28.

FIG. 31 is a side cross-sectional view of the implant and the expansiontool as shown in FIG. 30 taken along region 31.

FIGS. 32-35 are schematic illustrations of a posterior view of a medicaldevice according to an embodiment of the invention in a firstconfiguration (FIG. 32), a second (FIGS. 33 and 35) configuration and athird configuration (FIG. 34).

FIGS. 36-38 are schematic illustrations of a posterior view of a medicaldevice according to an embodiment of the invention in a firstconfiguration, a second configuration and a third configuration,respectively.

FIGS. 39-44 are posterior views of a medical device according to anembodiment of the invention inserted between adjacent spinous processesin a first lateral positions and a second lateral position.

FIG. 45 is a lateral view of the medical device illustrated in FIGS.39-44 inserted between adjacent spinous processes in a secondconfiguration.

FIG. 46 is a lateral view of a medical device according to an embodimentof the invention inserted between adjacent spinous processes in a secondconfiguration.

FIGS. 47 and 48 are front views of a medical device according to anembodiment of the invention in a first configuration and a secondconfiguration, respectively.

FIG. 49 is a schematic illustration of a posterior view of a medicaldevice according to an embodiment of the invention in a firstconfiguration disposed between two adjacent spinous processes.

FIG. 50 is a schematic illustration of a posterior view of a medicaldevice according to an embodiment of the invention in a secondconfiguration disposed between two adjacent spinous processes.

FIGS. 51 and 52 are perspective views of a medical device according toan embodiment of the invention in a first configuration and a secondconfiguration, respectively.

FIG. 53 is a posterior view of the medical device illustrated in FIGS.51 and 52 disposed between adjacent spinous processes in a secondconfiguration.

FIG. 54 is a lateral view taken from a proximal perspective A-A of themedical device illustrated in FIG. 53 disposed between adjacent spinousprocesses in a second configuration.

FIG. 55 is a cross-sectional front view of the medical deviceillustrated in FIGS. 51 and 52 in a second configuration.

FIG. 56 is a cross-sectional plan view taken along section A-A of themedical device illustrated in FIGS. 51 and 52 in a second configuration.

FIG. 57 is a cross-sectional front view of a medical device according toan embodiment of the invention in a second configuration.

FIGS. 58 and 59 are cross-sectional plan views taken along section A-Aof the medical device illustrated in FIG. 57 in a second configurationand a first configuration, respectively.

FIG. 60 is a cross-sectional front view of a medical device according toan embodiment of the invention in a second configuration.

FIGS. 61 through 63 are cross-sectional plan views taken along sectionA-A of the medical device illustrated in FIG. 60 in a secondconfiguration, a first configuration, and a third configurationrespectively.

FIGS. 64 and 65 are cross-sectional front views of a medical deviceaccording to an embodiment of the invention in a second configurationand a first configuration, respectively.

FIG. 66 is a cross-sectional front view of a medical device according toan embodiment of the invention in a second configuration.

FIG. 67 is a cross-sectional plan view taken along section A-A of themedical device illustrated in FIG. 66 in a second configuration.

FIGS. 68 and 69 are perspective views of a medical device according toan embodiment of the invention in a second configuration and a firstconfiguration, respectively.

FIGS. 70 and 71 are lateral views of a medical device according to anembodiment of the invention in a first configuration and a secondconfiguration, respectively.

FIGS. 72 and 73 are perspective views of the medical device illustratedin FIGS. 70 and 71 in a first configuration and a second configuration,respectively.

FIG. 74 is a cross-sectional plan view of the medical device illustratedin FIGS. 70 and 71 in a second configuration.

FIG. 75 is a posterior view of a portion of a medical device accordingto an embodiment of the invention disposed within a body between a pairof spinous processes.

FIG. 76 is a side view of the portion of medical device shown in FIG. 75taken along the lateral axis L_(L).

FIGS. 77 and 78 are a side view and a top plan view, respectively, ofthe portion of medical device shown in FIG. 75.

FIGS. 79 and 80 are a side view and a top plan view, respectively, of aportion of a medical device according to an embodiment of the invention.

FIG. 81 is a schematic illustration of a posterior view of an implant ina first configuration according to an embodiment of the inventiondisposed between a first spinous process and second spinous process.

FIG. 82 is a schematic illustration of a lateral view of the implantshown in FIG. 81 in the first configuration.

FIG. 83 is a schematic illustration of a posterior view of the implantshown in FIG. 81 in a second configuration.

FIG. 84 is a schematic illustration of a lateral view of the implantshown in FIG. 81 in a second first configuration.

FIG. 85 is a schematic illustration of a posterior view of an implant ina first configuration according to an embodiment of the inventiondisposed between a first spinous process and second spinous process.

FIG. 86 is a schematic illustration of a side view of the implant shownin FIG. 85 in the first configuration.

FIG. 87 is a schematic illustration of a lateral cross-sectional view ofthe implant shown in FIG. 85 in the first configuration taken along lineA-A.

FIG. 88 is a schematic illustration of a posterior view of the implantshown in FIG. 85 in a second configuration.

FIG. 89 is a schematic illustration of a side view of the implant shownin FIG. 85 in the second configuration.

FIG. 90 is a schematic illustration of a lateral cross-sectional view ofthe implant shown in FIG. 85 in the second configuration taken alongline A-A.

FIG. 91 is a schematic illustration of a posterior view of an implant ina first configuration according to an embodiment of the inventiondisposed between a first spinous process and second spinous process.

FIG. 92 is a schematic illustration of a side view of the implant shownin FIG. 91 in the first configuration.

FIG. 93 is a schematic illustration of a posterior view of the implantshown in FIG. 91 in a second configuration.

FIG. 94 is a schematic illustration of a side view of the implant shownin FIG. 91 in the second configuration.

FIG. 95 is a perspective view of an implant according to an embodimentof the invention in a first configuration.

FIG. 96 is a perspective view of the implant shown in FIG. 95 in asecond configuration.

FIG. 97 is a perspective view of a support member of the implant shownin FIG. 95.

FIG. 98 is a perspective view of a distal retention member of theimplant shown in FIG. 95.

FIG. 99 is a perspective view of a proximal retention member of theimplant shown in FIG. 95.

FIG. 100 is a perspective view of an implant according to an embodimentof the invention in a first configuration.

FIG. 101 is a front view of the implant shown in FIG. 100 in the firstconfiguration.

FIG. 102 is a bottom view of the implant shown in FIG. 100 in the firstconfiguration.

FIG. 103 is a perspective view of the implant shown in FIG. 100 in asecond configuration.

FIG. 104 is a front view of the implant shown in FIG. 100 in the secondconfiguration.

FIG. 105 is a bottom view of the implant shown in FIG. 100 in the secondconfiguration.

FIG. 106 is a cross-sectional perspective view of a deployment toolaccording to an embodiment of the invention.

FIG. 107 is a cross-sectional front view of the deployment tool shown inFIG. 106 engaging a proximal portion of the implant shown in FIG. 100.

FIG. 108 is a perspective view of the deployment tool shown in FIG. 106engaging the proximal portion of the implant shown in FIG. 100 in thefirst configuration.

FIG. 109 is a perspective view of the deployment tool shown in FIG. 106engaging the proximal portion the implant shown in FIG. 100 in thesecond configuration.

FIG. 110 is a cross-sectional front view of the deployment tool shown inFIG. 106 engaging a distal portion the implant shown in FIG. 100.

FIG. 111 is a perspective view of the deployment tool shown in FIG. 106engaging the distal portion the implant shown in FIG. 100 in the secondconfiguration.

FIG. 112 is a perspective view of the deployment tool shown in FIG. 106engaging the distal portion of the implant shown in FIG. 100 in thefirst configuration.

FIG. 113 is a flow chart illustrating a method of treating a spinalcondition according to an embodiment of the invention.

FIG. 114 is a schematic illustration of a posterior view of an implantin a first configuration according to an embodiment of the inventiondisposed between a first spinous process and second spinous process.

FIG. 115 is a schematic illustration of a lateral view of the implantshown in FIG. 114 in the first configuration.

FIG. 116 is a schematic illustration of a posterior view of the implantshown in FIG. 114 in a second configuration.

FIG. 117 is a schematic illustration of a lateral view of the implantshown in FIG. 114 in the second configuration.

FIG. 118 is a posterior view of an implant in a first configurationaccording to an embodiment of the invention disposed between a firstspinous process and second spinous process.

FIG. 119 is a cross-sectional posterior view of the implant shown inFIG. 118 in the first configuration.

FIG. 120 is a cross-sectional of the implant shown in FIG. 118 in thefirst configuration taken along line A-A.

FIG. 121 is a posterior view of the implant shown in FIG. 118 in thesecond configuration.

FIG. 122 is a cross-sectional posterior view of the implant shown inFIG. 118 in the second configuration.

FIG. 123 is a cross-sectional of the implant shown in FIG. 105 in thesecond configuration taken along line A-A.

FIG. 124 is a posterior view of an implant in a first configurationaccording to an embodiment of the invention disposed between a firstspinous process and second spinous process.

FIG. 125 is a lateral view of the implant shown in FIG. 111 in the firstconfiguration.

FIG. 126 is a posterior view of the implant shown in FIG. 111 in asecond configuration.

FIG. 127 is a lateral view of the implant shown in FIG. 111 in thesecond configuration.

FIG. 128 is a posterior view of an implant in a first configurationaccording to an embodiment of the invention disposed between a firstspinous process and second spinous process.

FIG. 129 is a posterior view of the implant shown in FIG. 115 in asecond configuration.

FIG. 130 is a flow chart illustrating a method according to anembodiment of the invention.

FIG. 131 is a flow chart illustrating a method according to anembodiment of the invention.

FIG. 132 is a schematic illustration of an embodiment of a medicaldevice shown within a schematic representation of a body.

FIG. 133 is an exploded side view of a medical device according to anembodiment of the invention.

FIG. 134 is a distal end view of the implant shown in FIG. 133 takenalong line 134-134 in FIG. 133.

FIG. 135 is a cross-sectional view of the insertion tool shown in FIG.133 taken along line 135-135 in FIG. 133.

FIG. 136 is a top view of a portion of the medical device of FIG. 133shown partially disposed within a body in a first position.

FIG. 137 is a top view of a portion of the medical device of FIG. 133shown partially disposed within a body in a second position.

FIG. 138 is a top view of a portion of a medical device according to anembodiment of the inventions shown partially disposed within a body.

FIG. 139 is an exploded side view of a medical device according toanother embodiment of the invention.

FIG. 140 is a distal end view of the implant shown in FIG. 139.

FIG. 141 is a distal end view of the implant shown in FIG. 139illustrating a portion of the guide member of FIG. 139 disposed within adistal end portion of the implant.

FIG. 142 is a side exploded view of a medical device according toanother embodiment of the invention.

FIG. 143 is a top view of the medical device of FIG. 142 and aninsertion tool shown partially disposed within a body.

FIG. 144 is a flowchart of a method according to an embodiment of theinvention.

FIG. 145 is a side view of a measurement device according to anembodiment of the invention.

FIG. 146 is a side view of the measurement device of FIG. 145 shownpartially disposed within a body and illustrating a first position and asecond position of the measurement device.

FIG. 147 is a side perspective view of a measurement device according toanother embodiment of the invention.

FIG. 148 is a side view of the measurement device of FIG. 147 shownadjacent to an image of a portion of a spine.

FIG. 149 is a schematic illustration of a posterior view of an implantin a first configuration according to an embodiment of the invention.

FIG. 150 is a schematic illustration of a posterior view of the implantshown in FIG. 149 in a second configuration disposed between a firstspinous process and second spinous process.

FIG. 151 is a schematic illustration of a posterior view of the implantshown in FIG. 149 in a third configuration.

FIG. 152 is a schematic illustration of a posterior view of the implantshown in FIG. 149 in a fourth configuration.

FIG. 153 is a schematic illustration of a posterior view of an implantin a first configuration according to an embodiment of the invention.

FIG. 154 is a schematic illustration of a posterior view of the implantshown in FIG. 153 in a second configuration disposed between a firstspinous process and second spinous process.

FIG. 155 is a schematic illustration of a posterior view of the implantshown in FIG. 153 in a third configuration.

FIG. 156 is a schematic illustration of a posterior view of the implantshown in FIG. 153 in a fourth configuration.

FIG. 157 is a flow chart illustrating a method of treating a spinalcondition according to an embodiment of the invention.

FIG. 158 is a flow chart illustrating a method of treating a spinalcondition according to an embodiment of the invention.

DETAILED DESCRIPTION

As used in this specification and the appended claims, the singularforms “a,” “an” and “the” include plural referents unless the contextclearly dictates otherwise. Thus, for example, the term “a member” isintended to mean a single member or a combination of members, “amaterial” is intended to mean one or more materials, or a combinationthereof. Furthermore, the words “proximal” and “distal” refer todirection closer to and away from, respectively, an operator (e.g.,surgeon, physician, nurse, technician, etc.) who would insert themedical device into the patient, with the tip-end (i.e., distal end) ofthe device inserted inside a patient's body first. Thus, for example,the implant end first inserted inside the patient's body would be thedistal end of the implant, while the implant end to last enter thepatient's body would be the proximal end of the implant.

In some embodiments, an apparatus includes a support member and aretention member. The support member has at least a portion configuredto be disposed between a first spinous process and a second spinousprocess. The retention member is movably coupled to an end portion ofthe support member. The retention member is configured to displace abodily tissue. The retention member is configured to move relative tothe support member from a first position to a second position. Theretention member is configured to limit movement of the support memberalong a longitudinal axis of the support member and relative to thefirst spinous process and the second spinous process when in the secondposition. In some embodiments, for example, the retention member and aportion of the support member collectively form a portion of a saddleconfigured to receive a portion of the first spinous process when theretention member is in the second position.

In some embodiments, an apparatus includes a first member and a secondmember. The first member has a longitudinal axis, a first surface, and asecond surface offset from the longitudinal axis by a non-zero angle. Atleast a portion of the first surface is configured to engage a spinousprocess. The second member is rotatably coupled to a distal end of thefirst member. The second member is configured to move relative to thefirst member between a first position and a second position. In someembodiments, for example, the second member is configured to rotaterelative to the first member about an axis substantially parallel to thelongitudinal axis of the first member. When the second member is in thefirst position, at least a portion of a surface of the second member isdisposed adjacent at least a portion of the second surface of the firstmember. In some embodiments, for example, the surface of the secondmember is in contact with the portion of the second surface of the firstmember when the second member is in the first position. When the secondmember is in the second position, the portion of the second surface ofthe second member is spaced apart from the portion of the second surfaceof the first member. The portion of the surface of the second member isconfigured to limit movement of the first member along the longitudinalaxis and relative to the spinous process when the second member is inthe second position.

In some embodiments, an apparatus includes a support member and aretention member rotatably coupled to the distal end of the supportmember. The support member has at least a portion configured to engageadjacent spinous processes. A distal end of the support member has across-sectional area normal to a longitudinal axis of the supportmember. The retention member has a cross-sectional area normal to thelongitudinal axis of the support member. The retention member isconfigured to rotate relative to the support member about an axissubstantially parallel to the longitudinal axis of the support memberfrom a first position to a second position. When the retention member isin the second position, the retention member is configured to limitmovement of the support member along the longitudinal axis and relativeto the first spinous process and the second spinous process. When theretention member is in the first position, the cross-sectional area ofthe retention member is within the cross-sectional area of the distalend of the support member when projected on a plane substantially normalto the longitudinal axis. When the retention member is in the secondposition, a portion of the cross-sectional area of the retention memberis outside of the cross-sectional area of the distal end of the supportmember when projected on the plane substantially normal to thelongitudinal axis.

In some embodiments, an apparatus includes a support member and aretention member movably coupled to the distal end of the supportmember. The support member has at least a portion configured to engageadjacent spinous processes. A distal end of the support member has afirst dimension along a first axis substantially normal to alongitudinal axis of the support member and a second dimension along asecond axis that is normal to both the longitudinal axis and the firstaxis. The second dimension is greater than the first dimension (e.g.,the distal end of the support member is rectangular). The retentionmember has a first dimension along the first axis and a second dimensionalong the second axis. The first dimension of the retention member isgreater than the second dimension of the support member and is nogreater than the first dimension of the support member. The seconddimension of the retention member is no greater than the seconddimension of the support member. The retention member is configured todisplace a bodily tissue. The retention member is configured to moverelative to the support member from a first position to a secondposition. In some embodiments, for example, when the retention member isin the first position, the first dimension of the retention member isaligned with the first dimension of the support member. When theretention member is in the second position, the first dimension of theretention member is aligned with the second dimension of the supportmember. In this manner, the retention member can limit movement of thesupport member along a longitudinal axis and relative to the spinousprocesses.

In some embodiments, an apparatus includes a support member, a retentionmember and a locking member. The support member is configured to bedisposed between a first spinous process and a second spinous process.The retention member is movably coupled to a distal end of the supportmember. The retention member is configured to move from a first positionto a second position to limit movement of the support member along alongitudinal axis and relative to the first spinous process and thesecond spinous process. The locking member is disposed within thesupport member and is configured to engage a first surface of theretention member when the retention member is in the first position suchthat the retention member is maintained in the first position. At leasta portion of the locking member is disposed outside of the supportmember and is configured to engage a second surface of the retentionmember when the retention member is in the second position such that theretention member is maintained in the second position. The secondsurface is different than the first surface.

In some embodiments, a method includes disposing at least a portion ofan implant between adjacent spinous processes. The implant includes asupport member and a retention member movably coupled to the supportmember. The retention member is rotated from a first position to asecond position such that the retention member retains a portion of theimplant between the adjacent spinous processes. In some embodiments, theretention member can be rotated about an axis substantially parallel toa longitudinal axis of the support member. The retention member isreversibly locked in the second position.

In some embodiments, an apparatus includes a support member, a firstretention member and a second retention member. The support member hasat least a portion configured to be disposed between a first spinousprocess and a second spinous process. The first retention member ismovably coupled to a first end portion of the support member. The secondretention member is movably coupled to a second end portion of thesupport member. The second retention member is coupled to the firstretention member such that the first retention member and the secondretention member are configured to collectively move relative to thesupport member from a first position to a second position. The firstretention member and the second retention member are configured to limitmovement of the support member relative to the first spinous process andthe second spinous process when in the second position.

In some embodiments, an apparatus includes a support member and aretention member rotatably coupled to the support member. The supportmember has an outer surface configured to be disposed between a firstspinous process and a second spinous process. The retention member has afirst end portion and a second end portion. The first end portion of theretention member is spaced apart from the outer surface of the supportmember by a first distance along an axis substantially normal to alongitudinal axis of the support member when the outer surface of thesupport member is disposed between the first spinous process and thesecond spinous process. The second end portion of the retention memberis spaced apart from the outer surface of the support member by a seconddistance along the axis substantially normal to the longitudinal axis ofthe support member when the outer surface of the support member isdisposed between the first spinous process and the second spinousprocess. The first end portion of the retention member and the secondend portion of the retention member are configured to cooperativelylimit movement of the support member along the longitudinal axis of thesupport member and relative to the first spinous process and the secondspinous process. In some embodiments, for example, the first end portionof the retention member is configured to engage the first spinousprocess when the outer surface of the support member is disposed betweenthe first spinous process and the second spinous process. In someembodiments, for example, the second end portion of the retention memberis configured to engage the second spinous process when the outersurface of the support member is disposed between the first spinousprocess and the second spinous process.

In some embodiments, an apparatus includes a support member and aretention member rotatably coupled to the support member about an axissubstantially normal to a longitudinal axis of the support member. Thesupport member has a portion configured to be disposed between a firstspinous process and a second spinous process. The retention member has afirst end portion, a second end portion, and a central portion. Thecentral portion of the retention member is disposed within the supportmember. The first end portion of the retention member is disposedoutside of a distal end portion of the support member and is configuredto engage the first spinous process when the portion of the supportmember is disposed between the first spinous process and the secondspinous process. The second end portion of the retention member isdisposed outside of a proximal end portion of the support member and isconfigured to engage the second spinous process when the portion of thesupport member is disposed between the first spinous process and thesecond spinous process.

In some embodiments, an apparatus includes a support member and aretention member rotatably coupled to the support member between a firstposition and a second position. The support member has a portionconfigured to be disposed between a first spinous process and a secondspinous process. A distal end portion of the support member has across-sectional area normal to a longitudinal axis of the supportmember. The retention member has an end portion and a central portion.The central portion is disposed within the support member. The endportion of the retention member is configured to displace a bodilytissue, such as for example, a supraspinous ligament. The end portion ofthe retention member has a cross-sectional area normal to thelongitudinal axis of the support member. The cross-sectional area of theend portion of the retention member is within the cross-sectional areaof the distal end portion of the support member when projected on aplane substantially normal to the longitudinal axis and when theretention member is in the first position. At least a portion of thecross-sectional area of the end portion of retention member is outsideof the cross-sectional area of the distal end of the support member whenprojected on the plane substantially normal to the longitudinal axis andwhen the retention member is in the second position.

In some embodiments, an apparatus includes a first elongate member and asecond elongate member rotatably coupled to the first elongate member.The first elongate member and the second elongate member collectivelyhave a first configuration and a second configuration. When the firstelongate member and the second elongate member are in the firstconfiguration, a longitudinal axis of the second elongate member issubstantially parallel to a longitudinal axis of the first elongatemember. When the first elongate member and the second elongate memberare in the second configuration, the longitudinal axis of the secondelongate member is angularly offset from the longitudinal axis of thefirst elongate member. When the first elongate member and the secondelongate member are in the second configuration, a portion of the firstelongate member is configured to contact a first side of a spinousprocess and a portion of the second elongate member is configured tocontact a second side of the spinous process opposite the first side tocooperatively limit movement of the first elongate member relative tothe spinous process.

In some embodiments, a method includes disposing at least a portion ofan implant between a first spinous process and a second spinous process.The implant includes a support member and a retention member rotatablycoupled to the support member. The retention member is rotated relativeto the support member from a first position to a second position suchthat a first end portion of the retention member is disposed outside ofa proximal end portion of the support member and a second end portion ofthe retention member is disposed outside a distal end portion of thesupport member. The first end portion of the retention member and thesecond end portion of the retention member cooperatively limit movementof the support member along a longitudinal axis of the support memberand relative to the first spinous process and the second spinousprocess. In some embodiments, the method can optionally include lockingthe retention member in the second position after the rotating.

In some embodiments, a method includes disposing at least a portion ofan implant between a first spinous process and a second spinous process.The implant includes a first elongate member and a second elongatemember rotatably coupled to the first elongate member. The secondelongate member is rotated relative to the first elongate member aboutan axis substantially normal to a longitudinal axis of the supportmember from a first position to a second position such that a portion ofthe first elongate member is engagable with a first surface of the firstspinous process and a portion of the second elongate member is engagablewith a second surface of the first spinous process opposite the firstsurface to limit lateral movement of the implant.

In one variation, a method provides for the insertion of an implantbetween adjacent bone structures. For example, an implant is insertedbetween adjacent spinous processes. The implant can be advanced within abody to a location between adjacent bone structures with an insertiontool and guided by a path defined by a guide member releasably coupledto the guide member. For example, the guide member can define a curvedpath through the body and a portion of the path goes between theadjacent bone structures.

In one embodiment, a method includes inserting at least a portion of aguide member between adjacent spinous processes. An implant that iscoupled to the guide member is advanced such that the guide member isadvanced along a curved path until at least a portion of the implant ispositioned between the adjacent spinous processes. An apparatusaccording to an embodiment of the invention includes an implantconfigured to be disposed between adjacent spinous processes and a guidemember having a proximal end releasably couplable to the implant. Theimplant is stationary relative to the guide member when the guide memberis releasably coupled to the implant. The guide member has a curvedshape and a distal tip configured to be percutaneously inserted into abody.

In another embodiment, a method includes percutaneously inserting aguide member at a first exterior location of a body. An implant coupledto a proximal end of the guide member is advanced along a path definedby the guide member such that during the advancing, a proximal end ofthe implant is at a fixed distance from the proximal end of the guidemember. A distal end of the guide member is advanced through a secondexterior location of the body.

In another embodiment, an apparatus includes an implant configured to beinserted into a body and a guide member. The guide member has a proximalend releasably couplable to the implant such that a distance between aproximal end of the implant and the proximal end of the guide member isfixed during insertion of the implant into the body. The guide memberhas a distal tip configured to be percutaneously inserted into the bodyat a first location and exit the body at a second location differentthan the first location.

In some embodiments, a method includes inserting an implant having asupport member and a retention member movably coupled to the supportmember such that at least a portion of the support member of the implantis disposed between a first spinous process and a second spinousprocess. The implant is rotated relative to the first spinous processand the second spinous process about an axis substantially normal to amid-line axis of a spinal column while the portion of the support memberis disposed between the first spinous process and the second spinousprocess. In some embodiments, the implant is rotated such that an innersurface of an end portion of the retention member is between an outersurface of the end portion of the retention member and the first spinousprocess. The retention member is translated relative to the supportmember.

In some embodiments, a method includes inserting an implant having afirst member, a second member and a third member such that at least aportion of the first member of the implant is disposed between a firstspinous process and a second spinous process. The implant is rotatedrelative to the first spinous process and the second spinous processsuch that an inner surface of the second member is between an outersurface of the second member and the first spinous process and an innersurface of the third member is between an outer surface of the thirdmember and the second spinous process. The second member is translatedrelative to the first member after the implant is rotated. In someembodiments, the third member is translated relative to the first memberafter the implant is rotated.

In some embodiments, an apparatus includes a support member and aretention member movably coupled to an end portion of the supportmember. The support member is configured to have at least a portiondisposed between a first spinous process and a second spinous process.The retention member is configured to translate relative to the supportmember from a first position to a second position along a longitudinalaxis of the retention member. The retention member is configured tolimit movement of the support member relative to the first spinousprocess and the second spinous process when in the second position.

In some embodiments, an apparatus includes a support member, a firstretention member and a second retention member. The support member isconfigured to have at least a portion disposed between a first spinousprocess and a second spinous process. The first retention member ismovably coupled to a first end portion of the support member. The firstretention member is configured to translate relative to the supportmember from a first position to a second position along a longitudinalaxis of the first retention member. The second retention member ismovably coupled to a second end portion of the support member. Thesecond retention member is configured to translate relative to thesupport member from a first position to a second position along alongitudinal axis of the second retention member. In some embodiments,the support member, the first retention member and the second retentionmember are collectively configured to rotate about an axis normal to amid-line axis of a spinal column when the portion of the support memberis disposed between the first spinous process and the second spinousprocess, the first retention member is in its first position and thesecond retention member is in its first position.

The term “body” is used here to mean a mammalian body. For example, abody can be a patient's body, or a cadaver, or a portion of a patient'sbody or a portion of a cadaver.

The term “parallel” or is used herein to describe a relationship betweentwo geometric constructions (e.g., two lines, two planes, a line and aplane, two curved surfaces, a line and a curved surface or the like) inwhich the two geometric constructions are substantially non-intersectingas they extend substantially to infinity. For example, as used herein, aline is said to be parallel to a curved surface when the line and thecurved surface do not intersect as they extend to infinity. Similarly,when a planar surface (i.e., a two-dimensional surface) is said to beparallel to a line, every point along the line is spaced apart from thenearest portion of the surface by a substantially equal distance. Twogeometric constructions are described herein as being “parallel” or“substantially parallel” to each other when they are nominally parallelto each other, such as for example, when they are parallel to each otherwithin a tolerance. Such tolerances can include, for example,manufacturing tolerances, measurement tolerances or the like.

The term “normal” is used herein to describe a relationship between twogeometric constructions (e.g., two lines, two planes, a line and aplane, two curved surfaces, a line and a curved surface or the like) inwhich the two geometric constructions intersect at an angle ofapproximately 90 degrees within at least one plane. For example, as usedherein, a line is said to be normal to a curved surface when the lineand the curved surface intersect at an angle of approximately 90 degreeswithin a plane. Two geometric constructions are described herein asbeing “normal” or “substantially normal” to each other when they arenominally normal to each other, such as for example, when they arenormal to each other within a tolerance. Such tolerances can include,for example, manufacturing tolerances, measurement tolerances or thelike.

FIG. 1 is a schematic illustration of a medical device according to anembodiment of the invention adjacent two adjacent spinous processes. Themedical device 10 includes a proximal portion 12, a distal portion 14and a central portion 16. The medical device 10 has a firstconfiguration in which it can be inserted between adjacent spinousprocesses S. The central portion 16 is configured to contact the spinousprocesses S to prevent over-extension/compression of the spinousprocesses S. In some embodiments, the central portion 16 does notsubstantially distract the adjacent spinous processes S. In otherembodiments, the central portion 16 does not distract the adjacentspinous processes S.

In the first configuration, the proximal portion 12, the distal portion14 and the central portion 16 are coaxial (i.e., share a commonlongitudinal axis). In some embodiments, the proximal portion 12, thedistal portion 14 and the central portion 16 define a tube having aconstant inner diameter. In other embodiments, the proximal portion 12,the distal portion 14 and the central portion 16 define a tube having aconstant outer diameter and/or inner diameter.

The medical device 10 can be moved from the first configuration to asecond configuration as illustrated in FIG. 2. In the secondconfiguration, the proximal portion 12 and the distal portion 14 arepositioned to limit lateral movement of the device 10 with respect tothe spinous processes S. The proximal portion 12 and the distal portion14 are configured to engage the spinous process (i.e., either directlyor through surrounding tissue) in the second configuration. For purposesof clarity, the tissue surrounding the spinous processes S is notillustrated.

In some embodiments, the proximal portion 12, the distal portion 14 andthe central portion 16 are monolithically formed. In other embodiments,one or more of the proximal portion 12, the distal portion 14 and thecentral portion 16 are separate components that can be coupled togetherto form the medical device 10. For example, the proximal portion 12 anddistal portion 14 can be monolithically formed and the central portioncan be a separate component that is coupled thereto.

In use, the spinous processes S can be distracted prior to inserting themedical device 10. Distraction of spinous processes is discussed below.When the spinous processes are distracted, a trocar can be used todefine an access passage for the medical device 10. In some embodiments,the trocar can be used to define the passage as well as distract thespinous processes S. Once an access passage is defined, the medicaldevice 10 is inserted percutaneously and advanced between the spinousprocesses, distal end 14 first, until the central portion 16 is locatedbetween the spinous processes S. Once the medical device 10 is in placebetween the spinous processes, the proximal portion 12 and the distalportion 14 are moved to the second configuration, either serially orsimultaneously.

In some embodiments, the medical device 10 is inserted percutaneously(i.e., through an opening in the skin) and in a minimally-invasivemanner. For example, as discussed in detail herein, the size of portionsof the implant is expanded after the implant is inserted between thespinous processes. Once expanded, the size of the expanded portions ofthe implant is greater than the size of the opening. For example, thesize of the opening/incision in the skin may be between 3 millimeters inlength and 25 millimeters in length. In some embodiments, the size ofthe implant in the expanded configuration is between 3 and 25millimeters.

FIG. 3 is a schematic illustration of a deformable element 18 that isrepresentative of the characteristics of, for example, the distalportion 14 of the medical device 10 in a first configuration. Thedeformable member 18 includes cutouts A, B, C along its length to defineweak points that allow the deformable member 18 to deform in apredetermined manner. Depending upon the depth d of the cutouts A, B, Cand the width w of the throats T1, T2, T3, the manner in which thedeformable member 18 deforms under an applied load can be controlled andvaried. Additionally, depending upon the length L between the cutouts A,B, C (i.e., the length of the material between the cutouts) the mannerin which the deformable member 18 deforms can be controlled and varied.

FIG. 4 is a schematic illustration of the expansion properties of thedeformable member 18 illustrated in FIG. 3. When a load is applied, forexample, in the direction indicated by arrow X, the deformable member 18deforms in a predetermined manner based on the characteristics of thedeformable member 18 as described above. As illustrated in FIG. 4, thedeformable member 18 deforms most at cutouts B and C due to theconfiguration of the cutout C and the short distance between cutouts Band C. In some embodiments, the length of the deformable member 18between cutouts B and C is sized to fit adjacent a spinous process.

The deformable member 18 is stiffer at cutout A due to the shallow depthof cutout A. As indicated in FIG. 4, a smooth transition is defined bythe deformable member 18 between cutouts A and B. Such a smoothtransition causes less stress on the tissue surrounding a spinousprocess than a more drastic transition such as between cutouts B and C.The dimensions and configuration of the deformable member 18 can alsodetermine the timing of the deformation at the various cutouts. Theweaker (i.e., deeper and wider) cutouts deform before the stronger(i.e., shallower and narrower) cutouts.

FIGS. 5 and 6 illustrate a spinal implant 100 in a first configurationand second configuration, respectively. As shown in FIG. 5, the spinalimplant 100 is collapsed in a first configuration and can be insertedbetween adjacent spinous processes. The spinal implant 100 has a firstexpandable portion 110, a second expandable portion 120 and a centralportion 150. The first expandable portion 110 has a first end 112 and asecond end 1140. The second expandable portion 120 has a first end 122and a second end 124. The central portion 150 is coupled between secondend 1140 and first end 122. In some embodiment, the spinal implant 100is monolithically formed.

The first expandable portion 110, the second expandable portion 120 andthe central portion 150 have a common longitudinal axis A along thelength of spinal implant 100. The central portion 150 can have the sameinner diameter as first expandable portion 110 and the second expandableportion 120. In some embodiments, the outer diameter of the centralportion 150 is smaller than the outer diameter of the first expandableportion 110 and the second expandable portion 120.

In use, spinal implant 100 is inserted percutaneously between adjacentspinous processes. The first expandable portion 110 is inserted firstand is moved past the spinous processes until the central portion 150 ispositioned between the spinous processes. The outer diameter of thecentral portion 150 can be slightly smaller than the space between thespinous processes to account for surrounding ligaments and tissue. Insome embodiments, the central portion directly contacts the spinousprocesses between which it is positioned. In some embodiments, thecentral portion of spinal implant 100 is a fixed size and is notcompressible or expandable.

The first expandable portion 110 includes expanding members 115, 117 and119. Between the expanding members 115, 117, 119, openings 111 aredefined. As discussed above, the size and shape of the openings 111influence the manner in which the expanding members 115, 117, 119 deformwhen an axial load is applied. The second expandable portion 120includes expanding members 125, 127 and 129. Between the expandingmembers 125, 127, 129, openings 121 are defined. As discussed above, thesize and shape of the openings 121 influence the manner in which theexpanding members 125, 127, 129 deform when an axial load is applied.

When an axial load is applied to the spinal implant 100, the spinalimplant 100 expands to a second configuration as illustrated in FIG. 6.In the second configuration, first end 112 and second end 1140 of thefirst expandable portion 110 move towards each other and expandingmembers 115, 117, 119 project substantially laterally away from thelongitudinal axis A. Likewise, first end 122 and second end 124 of thesecond expandable portion 120 move towards one another and expandingmembers 125, 127, 129 project laterally away from the longitudinal axisA. The expanding members 115, 117, 119, 125, 127, 129 in the secondconfiguration form projections that extend to positions adjacent to thespinous processes between which the spinal implant 100 is inserted. Inthe second configuration, the expanding members 115, 117, 119, 125, 127,129 inhibit lateral movement of the spinal implant 100, while thecentral portion 150 prevents the adjacent spinous processes from movingtogether any closer than the distance defined by the diameter of thecentral portion 150.

A spinal implant 200 according to an embodiment of the invention isillustrated in FIGS. 7-9 in various configurations. Spinal implant 200is illustrated in a completely collapsed configuration in FIG. 7 and canbe inserted between adjacent spinous processes. The spinal implant 200has a first expandable portion 210, a second expandable portion 220 anda central portion 250. The first expandable portion 210 has a first end212 and a second end 214. The second expandable portion 220 has a firstend 222 and a second end 224. The central portion 250 is coupled betweensecond end 214 and first end 222.

The first expandable portion 210, the second expandable portion 220 andthe central portion 250 have a common longitudinal axis A along thelength of spinal implant 200. The central portion 250 can have the sameinner diameter as first expandable portion 210 and the second expandableportion 220. The outer diameter of the central portion 250 is greaterthan the outer diameter of the first expandable portion 210 and thesecond expandable portion 220. The central portion 250 can bemonolithically formed with the first expandable portion 210 and thesecond expandable portion 220 or can be a separately formed sleevecoupled thereto or thereupon.

In use, spinal implant 200 is inserted percutaneously between adjacentspinous processes S. The first expandable portion 210 is inserted firstand is moved past the spinous processes S until the central portion 250is positioned between the spinous processes S. The outer diameter of thecentral portion 250 can be slightly smaller than the space between thespinous processes S to account for surrounding ligaments and tissue. Insome embodiments, the central portion 250 directly contacts the spinousprocesses S between which it is positioned. In some embodiments, thecentral portion 250 of spinal implant 200 is a fixed size and is notcompressible or expandable. In other embodiments, the central portion250 can compress to conform to the shape of the spinous processes.

The first expandable portion 210 includes expanding members 215, 217 and219. Between the expanding members 215, 217, 219, openings 211 aredefined. As discussed above, the size and shape of the openings 211influence the manner in which the expanding members 215, 217, 219 deformwhen an axial load is applied. Each expanding member 215, 217, 219 ofthe first expandable portion 210 includes a tab 213 extending into theopening 211 and an opposing mating slot 218. In some embodiments, thefirst end 212 of the first expandable portion 210 is rounded tofacilitate insertion of the spinal implant 200.

The second expandable portion 220 includes expanding members 225, 227and 229. Between the expanding members 225, 227, 229, openings 221 aredefined. As discussed above, the size and shape of the openings 221influence the manner in which the expanding members 225, 227, 229 deformwhen an axial load is applied. Each expanding member 225, 227, 229 ofthe second expandable portion 220 includes a tab 223 extending into theopening 221 and an opposing mating slot 228.

When an axial load is applied to the spinal implant 200, the spinalimplant moves to a partially expanded configuration as illustrated inFIG. 8. In the partially expanded configuration, first end 222 andsecond end 224 of the second expandable portion 220 move towards oneanother and expanding members 225, 227, 229 project laterally away fromthe longitudinal axis A. To prevent the second expandable portion 220from over-expanding, the tab 223 engages slot 228 and acts as a positivestop. As the axial load continues to be imparted to the spinal implant200 after the tab 223 engages slot 228, the load is transferred to thefirst expandable portion 210. Accordingly, the first end 212 and thesecond end 214 then move towards one another until tab 213 engages slot218 in the fully expanded configuration illustrated in FIG. 9. In thesecond configuration, expanding members 215, 217, 219 project laterallyaway from the longitudinal axis A. In some alternative embodiments, thefirst expandable portion and the second expandable portion expandsimultaneously under an axial load.

The order of expansion of the spinal implant 200 can be controlled byvarying the size of openings 211 and 221. For example, in theembodiments shown in FIGS. 7-9, the opening 221 is slightly larger thanthe opening 211. Accordingly, the notches 226 are slightly larger thanthe notches 216. As discussed above with respect to FIGS. 3 and 4, forthis reason, the second expandable portion 220 will expand before thefirst expandable portion 210 under an axial load.

In the second configuration, the expanding members 215, 217, 219, 225,227, 229 form projections that extend adjacent the spinous processes S.Once in the second configuration, the expanding members 215, 217, 219,225, 227, 229 inhibit lateral movement of the spinal implant 200, whilethe central portion 250 prevents the adjacent spinous processes frommoving together any closer than the distance defined by the diameter ofthe central portion 250.

The portion P of each of the expanding members 215, 217, 219, 225, 227,229 proximal to the spinous process S expands such that portion P issubstantially parallel to the spinous process S. The portion D of eachof the expanding members 215, 217, 219, 225, 227, 229 distal from thespinous process S is angled such that less tension is imparted to thesurrounding tissue.

In the second configuration, the expanding members 225, 227, 229 areseparate by approximately 120 degrees from an axial view as illustratedin FIG. 10. While three expanding members are illustrated, two or moreexpanding members may be used and arranged in an overlapping orinterleaved fashion when multiple implants 200 are inserted betweenmultiple adjacent spinous processes. Additionally, regardless of thenumber of expanding members provided, the adjacent expanding membersneed not be separated by equal angles or distances.

The spinal implant 200 is deformed by a compressive force impartedsubstantially along the longitudinal axis A of the spinal implant 200.The compressive force is imparted, for example, by attaching a rod (notillustrated) to the first end 212 of the first expandable portion 210and drawing the rod along the longitudinal axis while imparting anopposing force against the second end 224 of the second expandableportion 220. The opposing forces result in a compressive force causingthe spinal implant 200 to expand as discussed above.

The rod used to impart compressive force to the spinal implant 200 canbe removably coupled to the spinal implant 200. For example, the spinalimplant 200 can include threads 208 at the first end 212 of the firstexpandable portion 210. The force opposing that imparted by the rod canbe applied by using a push bar (not illustrated) that is removablycoupled to the second end 224 of the second expandable portion 220. Thepush rod can be aligned with the spinal implant 200 by an alignmentnotch 206 at the second end 224. The spinal implant 200 can also bedeformed in a variety of other ways, using a variety of expansiondevices (also referred to herein as insertion tools, deployment toolsand/or removal tools). While various types of implants are illustratedwith various types of expansion devices, the expansion devices describedherein can be used with any of the implants described herein.

FIGS. 11-16 illustrate an expansion device 1500 (also referred to hereinas an insertion tool or a deployment tool) according to an embodiment ofthe invention. Although no particular implant is illustrated in FIGS.11-16, any of the implants described herein, such as, for example,implant 200 (see FIG. 7), can be used with the expansion device 1500.The expansion device 1500 includes a guide handle 1510, a knob assembly1515, a shaft 1520, a rod 1570 and an implant support portion 1530. Theexpansion device 1500 is used to insert an implant (not illustrated) inbetween adjacent spinous processes and expand the implant such that itis maintained in position between the spinous processes as describedabove. Both the guide handle 1510 and the knob assembly 1515 can begrasped to manipulate the expansion device 1500 to insert the implant.As described in more detail herein, the knob assembly 1515 is configuredsuch that as the knob assembly 1515 is actuated, the rod 1570 translatesand/or rotates within the shaft 1520; when the rod 1570 translates, theimplant (not illustrated) is moved between its collapsed configurationand its expanded configuration; when the rod 1570 rotates, the implantis disengaged from the rod 1570.

As best illustrated in FIGS. 15 and 16, the implant support portion 1530includes a receiving member 1538 and a spacer 1532. The receiving member1538 includes a side wall 1540 that is coupled to and supported by thedistal end of the shaft 1520. The side wall 1540 defines an alignmentprotrusion 1536 and a receiving area 1542 configured to receive aportion of the spacer 1532. The implant slides over spacer 1532 untilits proximal end is received within a recess 1534 defined by the sidewall 1540 and the outer surface of the spacer 1532. The alignmentprotrusion 1536 is configured to mate with a corresponding notch on theimplant (see, e.g., alignment notch 206 in FIG. 7) to align the implantwith respect to the expansion device. Once the implant is aligned withinthe implant support portion 1530, the distal end of the implant isthreadedly coupled to the distal end of rod 1570.

As illustrated, the spacer 1532 ensures that the implant is alignedlongitudinally during the insertion and expansion process. The spacer1532 can also be configured to maintain the shape of the implant duringinsertion and to prevent the expandable portions of the implant fromextending inwardly during deployment of the implant. For example, insome embodiments, the spacer 1532 can be constructed from a solid,substantially rigid material, such as stainless steel, having an outerdiameter and length corresponding to the inner diameter and length ofthe implant. In other embodiments, the expansion device can beconfigured to be used with implants that include an inner coreconfigured to provide structural support to the implant (see, forexample, FIGS. 17-23). In such embodiments, as described in more detailherein, the spacer of the insertion tool can be configured to cooperatewith the inner core of the implant to provide the alignment andstructural support of the implant during insertion and expansion.

The knob assembly 1515 includes an upper housing 1517 that threadedlyreceives the shaft 1520, an actuator knob 1550 and a release knob 1560as best illustrated in FIG. 14. Upper housing 1517 includes internalthreads 1519 that mate with external threads 1521 on shaft 1520. Theproximal end of rod 1570 is coupled to the knob assembly 1515 by anadapter 1554, which is supported by two thrust bearings 1552. Actuatorknob 1550 is coupled to the upper housing 1517 and is engaged with theadapter 1554 such that when actuator knob 1550 is turned in thedirection indicated by arrows E (see FIG. 13), the rod 1570 translatesaxially relative to the shaft 1520 towards the proximal end of thedevice 1500, thereby acting as a draw bar and opposing the movement ofthe implant in the distal direction. In other words, when the implant isinserted between adjacent spinous processes and the actuator knob 1515is turned, the distal end of the implant support portion 1530 imparts anaxial force against the proximal end of the implant, while the rod 1570causes an opposing force in the proximal direction. In this manner, theforces imparted by the implant support portion and the rod 1570 causeportions of the implant to expand in a transverse configuration suchthat the implant is maintained in position between the spinous processesas described above. The expansion device 1500 can also be used to movethe implant from its expanded configuration to its collapsedconfiguration by turning the actuator knob 1550 in the oppositedirection.

Once the implant is in position and fully expanded, the release knob1560 is turned in the direction indicated by arrow R (see FIG. 13)thereby causing the rod 1570 to rotate within the shaft 1520. In thismanner, the implant can be disengaged from the rod 1570. During thisoperation, the implant is prevented from rotating by the alignmentprotrusion 1536, which is configured to mate with a corresponding notchon the implant. Once the implant is decoupled from the rod 1570, theexpansion tool 1500 can then be removed from the patient.

Although the knob assembly 1515 is shown and described as including anactuator knob 1550 and a release knob 1560 that are coaxially arrangedwith a portion of the release knob 1560 being disposed within theactuator knob 1550, in some embodiments, the release knob is disposedapart from the actuator knob. In other embodiments, the release knob andthe actuator knob are not coaxially located. In yet other embodiments,the knob assembly 1515 does not include knobs having a circular shape,but rather includes levers, handles or any other device suitable foractuating the rod relative to the shaft as described above.

FIGS. 17-23 illustrate an implant 6610 according to another embodimentof the invention. The implant 6610 can be moved between a collapsedconfiguration, as shown in FIGS. 17 and 18, and an expandedconfiguration, as shown in FIGS. 19-23. The implant 6610 includes anouter shell 6670 having a distal portion 6612, a proximal portion 6614,and a central portion 6616. The outer shell 6670 defines a series ofopenings 6618 disposed between the distal portion 6612 and the centralportion 6616, and the proximal portion 6614 and the central portion6616. The outer shell 6670 includes a series of tabs 6620, a pair ofwhich are disposed opposite each other, along the longitudinal axis ofthe implant 6610, on either side of each opening 6618. The outer shell6670 also includes expandable portions 6640, which form extensions 6642that extend radially from the outer shell 6670 when the implant 6610 isin the expanded configuration. As illustrated best in FIGS. 19-23, thearrangement of the openings 6618 and the tabs 6620 effect the shapeand/or size of the extensions 6642. In some embodiments, the opposingtabs 6620 can be configured to engage each other when the implant 6610is in the expanded configuration, thereby serving as a positive stop tolimit the amount of expansion. In other embodiments, for example, theopposing tabs 6620 can be configured to engage each other during theexpansion process, thereby serving as a positive stop, but remain spacedapart when the implant 6610 is in the expanded configuration (see, forexample, FIGS. 19-23). In such embodiments, the elastic properties ofthe extensions 6642 can cause a slight “spring back,” thereby causingthe opposing tabs 6620 to be slightly spaced apart when the expansiondevice (also referred to as an insertion tool or a deployment tool) isdisengaged from the implant 6610.

As illustrated best in FIG. 17, when the implant is in the collapsedconfiguration, the expandable portions 6640 are contoured to extendslightly radially from remaining portions of the outer shell 6670. Inthis manner, the expandable portions 6640 are biased such that when acompressive force is applied, the expandable portions 6640 will extendoutwardly from the outer shell 6670. The expandable portions 6640 can bebiased using any suitable mechanism. In some embodiments, for example,the expandable portions can be biased by including a notch in one ormore locations along the expandable portion, as previously described. Inother embodiments, the expandable portions can be biased by varying thethickness of the expandable portions in an axial direction. In yet otherembodiments, the expandable portions can be stressed or bent prior toinsertion such that the expandable portions are predisposed to extendoutwardly when a compressive force is applied to the implant. In suchembodiments, the radius of the expandable portions is greater than thatof the remaining portions of the implant (e.g., the remainingcylindrical portions of the implant).

The implant 6610 also includes an inner core 6672 disposed within alumen 6658 defined by the outer shell 6670. The inner core 6672 isconfigured to maintain the shape of the implant 6610 during insertion,to prevent the expandable portions from extending inwardly into a regioninside of the outer shell 6670 during deployment and/or to maintain theshape of the central portion 6616 once the implant is in its desiredposition. As such, the inner core 6670 can be constructed to provideincreased compressive strength to the outer shell 6670. In other words,the inner core 6672 can provide additional structural support to outershell 6670 (e.g., in a direction transverse to the axial direction) byfilling at least a portion of the region inside outer shell 6670 (e.g.,lumen 6658) and contacting the walls of outer shell 6670. This canincrease the amount of compressive force that can be applied to theimplant 6610 while the implant 6610 still maintains its shape and, forexample, the desired spacing between adjacent spinous processes. In someembodiments, the inner core 6672 can define a lumen 6673, while in otherembodiments, the inner core 6672 can have a substantially solidconstruction. As illustrated, the inner core 6672 is fixedly coupled tothe outer shell 6670 with a coupling portion 6674, which is configuredto be threadedly coupled to the distal portion 6612 of the outer shell6670. The distal end of the coupling portion 6674 of the inner core 6672includes an opening 6675 configured to receive a tool configured todeform the distal end of the coupling portion 6674. In this manner oncethe inner core 6672 is threadedly coupled to the outer shell 6670, thecoupling portion 6674 can be deformed or peened to ensure that the innercore 6672 does not become inadvertently decoupled from the outer shell6670. In some embodiments, an adhesive, such as a thread-lockingcompound can be applied to the threaded portion of the coupling portion6674 to ensure the that the inner core 6672 does not inadvertentlybecome decoupled from the outer shell 6670. Although illustrated asbeing threadedly coupled, the inner core 6672 can be coupled to theouter shell 6670 by any suitable means. In some embodiments, forexample, the inner core 6672 can be coupled to the central portion 6616of the outer shell 6670 by, for example, a friction fit. In otherembodiments, the inner core 6672 can be coupled to the outer shell 6670by an adhesive. The inner core 6672 can have a length such that theinner core 6672 is disposed within the lumen 6658 along substantiallythe entire length of the outer shell 6670 or only a portion of thelength of the outer shell 6670.

The proximal portion of the inner core 6672 includes an opening 6673configured to receive a portion of an expansion device 7500 (alsoreferred to as an insertion tool or a deployment tool), as shown inFIGS. 24-31. The expansion device 7500 is similar to the expansiondevice 1500 shown and described above (see e.g. FIGS. 11-16). Theexpansion device 7500 differs, however, from expansion device 1500 inthat the expansion device 7500 includes spacer 7532 configured tocooperate with the inner core 6672 of the implant 6610. In such anarrangement, the threaded portion of rod 7570 of the expansion device7500 removably engages to the internal threads 6676 of the inner core6672 of the implant 6610, rather than coupling directly to the distalportion of the implant (as shown in FIGS. 15 and 16). Although the innercore 6672 is shown as being threadedly coupled to the expansion device7500, the inner core 6672 can be removably coupled to the expansiondevice 7500 by any suitable means, such as a protrusion and detentarrangement.

In use, once the implant 6610 is positioned on the implant supportportion 7530 of the expansion tool 7500 (see FIGS. 24 and 25), theimplant is inserted into the patient's body and disposed betweenadjacent spinous processes. Once disposed between adjacent spinousprocesses, the expansion device can be used to move the inner core 6672axially towards the proximal portion 6614 of the implant 6610 whilesimultaneously maintaining the position of the proximal portion 6614 ofthe implant 6610, as shown in FIGS. 29 and 31. In this manner, acompressive force is applied along the longitudinal axis of the outershell 6670, thereby causing the outer shell 6670 to fold or bend to formextensions 6642 as described above. As illustrated, a portion of thespacer 7532 is received within the receiving area 7542 of the supportportion 7530 as the implant 6610 is placed in the expandedconfiguration. Similarly, to move the implant 6610 from the expandedconfiguration to the collapsed configuration, the expansion device isactuated in the opposite direction to impart an axial force on thedistal portion 6612 of the outer shell 6610 in a distal direction,moving the distal portion 6612 distally, and moving the implant 6610 tothe collapsed configuration.

Once the implant 6610 is in its expanded configuration (see FIGS.28-31), the implant 6610 can be disengaged from the expansion device7500 by disengaging the distal portion of the rod 7570 from the opening6673. The rod 7570 can be disengaged by actuating the knob assembly 7515rotate the rod 7570 relative to the shaft 7520, as discussed above.

Although shown and described above without reference to any specificdimensions, in some embodiments, the outer shell 6670 can have acylindrical shape having a length of approximately 34.5 mm (1.36 inches)and a diameter between 8.1 and 14.0 mm (0.32 and 0.55 inches). In someembodiments, the wall thickness of the outer shell can be approximately5.1 mm (0.2 inches).

Similarly, in some embodiments, the inner core 6672 can have acylindrical shape having an overall length of approximately 27.2 mm(1.11 inches) and a diameter between 8.1 and 14.0 mm (0.32 and 0.55inches).

In some embodiments, the shape and size of the openings 6618 locatedadjacent the distal portion 6612 can be the same as that for theopenings 6618 located adjacent the proximal portion 6614. In otherembodiments, the openings 6618 can have different sizes and/or shapes.In some embodiments, the openings 6618 can have a length ofapproximately 11.4 mm (0.45 inches) and a width between 4.6 and 10 mm(0.18 and 0.40 inches).

Similarly, the shape and size of the tabs 6620 can be uniform ordifferent as circumstances dictate. In some embodiments, for example,the longitudinal length of the tabs 6620 located adjacent the proximalportion 6614 can be shorter than the longitudinal length of the tabs6620 located adjacent the distal portion 6612. In this manner, as theimplant is moved from the collapsed configuration to the expandedconfiguration, the tabs adjacent the distal portion will engage eachother first, thereby limiting the expansion of the expandable portions6640 adjacent the distal portion 6612 to a greater degree than theexpandable portions 6642 located adjacent the proximal portion 6614. Inother embodiments, the longitudinal length of the tabs can be the same.In some embodiments, the longitudinal length of the tabs can be between1.8 and 2.8 mm (0.07 and 0.11 inches). In some embodiments, the endportions of opposing tabs 6620 can have mating shapes, such as matingradii of curvature, such that the opposing tabs 6620 engage each otherin a predefined manner.

Although illustrated as having a generally rectangular shape, theexpandable portions 6640 and the resulting extensions 6642 can be of anysuitable shape and size. In some embodiments, for example, theexpandable portions can have a longitudinal length of approximately 11.4mm (0.45 inches) and a width between 3.6 and 3.8 mm (0.14 and 0.15inches). In other embodiments, size and/or shape of the expandableportions located adjacent the proximal portion 6614 can be differentthan the size and/or shape of the tabs 6620 located adjacent the distalportion 6612. Moreover, as described above, the expandable portions 6640can be contoured to extend slightly radially from the outer shell 6670.In some embodiments, for example, the expandable portions can have aradius of curvature of approximately 12.7 mm (0.5 inches) along an axisnormal to the longitudinal axis of the implant.

In some embodiments, the expandable portions 6640 and the outer shell6670 are monolithically formed. In other embodiments, the expandableportions 6640 and the outer shell 6670 are formed from separatecomponents having different material properties. For example, theexpandable portions 6640 can be formed from a material having a greateramount of flexibility, while the outer shell 6670 can be formed from amore rigid material. In this manner, the expandable portions 6640 can beeasily moved from the collapsed configuration to the expandedconfiguration, while the outer shell 6670 is sufficiently strong toresist undesirable deformation when in use.

In one embodiment, an apparatus includes a first body coupled to asecond body. The first body and the second body collectively areconfigured to be releasably coupled to an implant device configured tobe disposed between adjacent spinous processes. A first engaging portionis coupled to the first body, and a second engaging portion is coupledto the second body. The first engaging portion and/or the secondengaging portion is configured to be received within a first openingdefined by the implant device. The first body configured to be movedrelative to the second body such that a distance between the firstengaging portion and the second engaging portion is moved between afirst distance and a second distance, and simultaneously a length of theimplant device is moved between a first length and a second length.

In another embodiment, a kit includes an implant that is reconfigurablebetween an expanded configuration and a collapsed configuration whiledisposed between adjacent spinous processes. The implant has alongitudinal axis and defines an opening. A deployment tool isconfigured to be releasably coupled to the implant. The deployment toolincludes an engaging portion configured to be removably received withinthe opening of the implant and extend in a transverse direction relativeto the longitudinal axis when the deployment tool is coupled to theimplant. The deployment tool is configured to move the implant betweenthe collapsed configuration and the expanded configuration while theimplant is disposed between the adjacent spinous processes.

FIGS. 32-35 are schematic illustrations of a posterior view of a medicaldevice 4000 according to an embodiment of the invention positionedadjacent two adjacent spinous processes S in a first configuration (FIG.32), a second configuration (FIGS. 33 and 35) and a third configuration(FIG. 34). The medical device 4000 includes an expandable member 4002having an inner area (not shown) and an outer surface 4010. The outersurface 4010 is configured to be disposed between the spinous processesS to prevent over-extension/compression of the spinous processes S. Insome embodiments, the expandable member 4002 distracts the adjacentspinous processes S. In other embodiments, the expandable member 4002does not distract the adjacent spinous processes S.

The expandable member 4002 has a first configuration, a secondconfiguration and a third configuration. When in each configuration, theexpandable member 4002 has an associated volume. As illustrated in FIG.32, the first configuration represents a substantially contractedcondition in which the expandable member 4002 has a minimal volume. Whenthe expandable member 4002 is in the first configuration, the medicaldevice 4000 is inserted between the adjacent spinous processes S. Asillustrated in FIGS. 33 and 35, the second configuration represents anexpanded condition in which the expandable member 4002 has a largevolume. When the expandable member 4002 is in the second configuration,the outer surface 4010 of the medical device 4000 contacts the adjacentspinous processes S during at least a portion of the range of motion ofthe spinous processes. As illustrated in FIG. 34, the thirdconfiguration represents a partially expanded condition in which theexpandable member 4002 has a volume between that associated with thefirst configuration and that associated with the second configuration.When the expandable member 4002 is in the third configuration, themedical device 4000 can be repositioned between the adjacent spinousprocesses, as indicated by the arrow in FIG. 34. The medical device canthen be subsequently re-expanded into the second configuration, asillustrated in FIG. 35.

FIGS. 36-38 are schematic illustrations of a posterior view of themedical device 4000 positioned adjacent two adjacent spinous processes Sin a first configuration, a second configuration and a thirdconfiguration, respectively. As described above, when the expandablemember 4002 is in the first configuration, the medical device 4000 isinserted between the adjacent spinous processes S. The expandable member4002 is then expanded to the second configuration, in which the outersurface 4010 of the medical device 4000 is disposed between the adjacentspinous processes S. The expandable member 4002 is then contracted tothe third configuration to facilitate removal of the medical device4000, as shown in FIG. 38. In some embodiments, the third configurationcan be the same as the first configuration.

In use, the adjacent spinous processes S can be distracted prior toinserting the medical device 4000 into a body, as described herein. Whenthe spinous processes S are distracted, a trocar (not shown) can be usedto define an access passageway (not shown) for the medical device 4000.In some embodiments, the trocar can be used to define the passage aswell as to distract the spinous processes S. Once an access passagewayis defined, the medical device 4000 is inserted percutaneously andadvanced between the spinous processes S and placed in the desiredposition between the adjacent spinous processes S. Once the medicaldevice 4000 is in the desired position, the expandable member isexpanded to the second condition, causing the outer surface 4010 toengage the spinous processes S.

In some embodiments, the adjacent spinous processes can be distracted bya first expandable member (not shown) configured to distract bone. Upondistraction, the first expandable member is contracted and removed fromthe body. The medical device 4000 is then inserted percutaneously,advanced between the spinous processes S, placed in the desired positionand expanded, as described above.

In some embodiments, the medical device 4000 is inserted percutaneously(i.e., through an opening in the skin) and in a minimally-invasivemanner. For example, as discussed in detail herein, the overall sizes ofportions of the medical device 4000 are increased by transitioning theexpandable member 4002 from the first configuration to the secondconfiguration after the medical device 4000 is inserted between theadjacent spinous processes S. When in the expanded second configuration,the sizes of portions of the medical device 4000 are greater than thesize of the opening. For example, the size of the opening/incision inthe skin can be between 3 millimeters in length and 25 millimeters inlength across the opening. In some embodiments, the size of the medicaldevice 4000 in the expanded second configuration is between 3 and 25millimeters across the opening.

FIGS. 39-44 are posterior views of a spinal implant 4100 according to anembodiment of the invention inserted between adjacent spinous processesS in a first lateral position (FIG. 41) and a second lateral position(FIG. 43). The spinal implant 4100 includes an expandable member 4102, asensor 4112 and a valve 4132. The expandable member 4102 has an innerarea (not shown), an outer surface 4110, a support portion 4118, aproximal retention portion 4114 and a distal retention portion 4116. Theexpandable member 4102 is repeatably positionable in a firstconfiguration (FIG. 40), a second configuration (FIGS. 41, 43 and 44)and a third configuration (FIG. 42). When in each configuration, theexpandable member 4102 has an associated volume, as will be discussedbelow.

In use, the spinal implant 4100 is positioned in the substantiallycontracted first configuration during insertion and/or removal (see FIG.40). As discussed above, the spinal implant 4100 is insertedpercutaneously between adjacent spinous processes S. The distalretention portion 4116 of the expandable member 4102 is inserted firstand is moved past the spinous processes S until the support portion 4118is positioned between the spinous processes S. When in the firstconfiguration, the support portion 4118 can be can be sized to accountfor ligaments and tissue surrounding the spinous processes S. Forpurposes of clarity, such surrounding ligaments and tissue are notillustrated.

As illustrated in FIG. 41, once in position, the expandable member 4102is expanded into the second configuration by conveying a fluid (notshown) from an area outside of the expandable member 4102 to the innerarea of the expandable member 4102. The fluid is conveyed by anexpansion tool 4130, such as a catheter, that is matingly coupled to thevalve 4132. The valve 4132 can be any valve suitable for sealablyconnecting the inner area of the expandable member 4102 to an areaoutside of the expandable member 4102. For example, in some embodiments,the valve 4132 can be, for example a poppet valve, a pinch valve or atwo-way check valve. In other embodiments, the valve includes a couplingportion (not shown) configured to allow the expansion tool 4130 to berepeatably coupled to and removed from the valve 4132. For example, insome embodiments, the valve 4132 can include a threaded portionconfigured to matingly couple the expansion tool 4130 and the valve4132.

The fluid is configured to retain fluidic properties while resident inthe inner area of the expandable member 4102. In this manner, the spinalimplant 4100 can be repeatably transitioned from the expanded secondconfiguration to the first configuration and/or the third configurationby removing the fluid from the inner area of the expandable member 4102.In some embodiments, the fluid can be a biocompatible liquid havingconstant or nearly constant properties. Such liquids can include, forexample, saline solution. In other embodiments, the fluid can be abiocompatible liquid configured to have material properties that changeover time while still retaining fluidic properties sufficient to allowremoval of the fluid. For example, the viscosity of a fluid can beincreased by adding a curing agent or the like. In this manner, thefluid can provide both the requisite structural support while retainingthe ability to be removed from the inner area of the expandable member4102 via the valve 4132. In yet other embodiments, the fluid can be abiocompatible gas.

The outer surface 4110 of the support portion 4118 can distract theadjacent spinous processes S as the expandable member 4102 expands tothe second configuration, as indicated by the arrows shown in FIG. 41.In some embodiments, the support portion 4118 does not distract theadjacent spinous processes S. For example, as discussed above, theadjacent spinous processes S can be distracted by a trocar and/or anyother device suitable for distraction.

When in the second configuration, the outer surface 4110 of the supportportion 4118 is configured to engage the spinous processes S for atleast a portion of the range of motion of the spinous processes S toprevent over-extension/compression of the spinous processes S. In someembodiments, the engagement of the spinous processes S by the outersurface 4110 of the support portion 4118 is not continuous, but occursupon spinal extension.

When in the second configuration, the proximal retention portion 4114and the distal retention portion 4116 each have a size S1 (shown in FIG.45) that is greater than the vertical distance D1 (shown in FIG. 45)between the spinous processes. In this manner, the proximal retentionportion 4114 and the distal retention portion 4116 are disposed adjacentthe sides of spinous processes S (i.e., either through direct contact orthrough surrounding tissue), thereby limiting movement of the spinalimplant 4100 laterally along a longitudinal axis of the support portion4118.

The expandable member 4102 can be made from any number of biocompatiblematerials, such as, for example, PET, Nylons, cross-linked Polyethylene,Polyurethanes, and PVC. In some embodiments, the chosen material can besubstantially inelastic, thereby forming a low-compliant expandablemember 4102. In other embodiments, the chosen material can have a higherelasticity, thereby forming a high-compliant expandable member 4102. Inyet other embodiments, the expandable member 4102 can be made from acombination of materials such that one portion of the expandable member4102, such as the support portion 4118, can be low-compliant while otherportions of the expandable member 4102, such as the proximal retentionportion 4114 and/or distal retention portion 4116 are more highlycompliant. In yet other embodiments, a portion of the expandable member4102 can include a rigid, inflexible material to provide structuralstiffness. For example, the support portion 4118 can be constructed of acomposite material that includes a rigid, inflexible material tofacilitate distraction of the adjacent spinous processes.

In some embodiments, the expandable member 4102 includes a radiopaquematerial, such as bismuth, to facilitate tracking the position of thespinal implant 4100 during insertion and/or repositioning. In otherembodiments, the fluid used to expand the expandable member 4102includes a radiopaque tracer to facilitate tracking the position of thespinal implant 4100.

In the illustrated embodiment, the spinal implant 4100 includes a sensor4112 coupled to the expandable member 4102. In some embodiments, thesensor 4112 is a strain gauge sensor that measures a force applied tothe support portion 4118 of the expandable member 4102. The sensor 4112can include multiple strain gauges to facilitate measuring multipleforce quantities, such as a compressive force and/or a tensile force. Inother embodiments, the sensor 4112 is a variable capacitance typepressure sensor configured to measure a force and/or a pressure of thefluid contained within the inner portion of the expandable member 4102.In yet other embodiments, the sensor 4112 is a piezoelectric sensor thatmeasures a pressure of the fluid contained within the inner portion ofthe expandable member 4102. In still other embodiments, the spinalimplant 4100 can include multiple sensors 4112 located at variouslocations to provide a spatial profile of the force and/or pressureapplied to the expandable member 4102. In this manner, a practitionercan detect changes in the patient's condition, such those that mayresult in a loosening of the spinal implant 4100.

In some embodiments, the sensor 4112 can be remotely controlled by anexternal induction device. For example, an external radio frequency (RF)transmitter (not shown) can be used to supply power to and communicatewith the sensor 4112. In other embodiments, an external acoustic signaltransmitter (not shown) can be used to supply power to and communicatewith the sensor 4112. In such an arrangement, for example, the sensorcan include a pressure sensor, of the types described above, formeasuring a pressure; an acoustic transducers, and an energy storagedevice. The acoustic transducer converts energy between electricalenergy and acoustic energy. The energy storage device stores theelectrical energy converted by the acoustic transducer and supplies theelectrical energy to support the operation of the pressure sensor. Inthis manner, acoustic energy from an external source can be received andconverted into electrical energy used to power the pressure sensor.Similarly, an electrical signal output from the pressure sensor can beconverted into acoustic energy and transmitted to an external source.

At times, the spinal implant 4100 may need to be repositioned. Suchrepositioning can be required, for example, to optimize the lateralposition of the support portion 4118 during the insertion process. Inother instances, the spinal implant 4100 can require repositioningsubsequent to the insertion process to accommodate changes in theconditions of the patient. In yet other instances, the spinal implant4100 can be removed from the patient. To allow for such repositioningand/or removal, the spinal implant is repeatably positionable in thefirst configuration, the second configuration and/or the thirdconfiguration. In FIG. 42, for example, the expandable member 4102 iscontracted to the third configuration by removing all or a portion ofthe fluid contained in the inner area, as described above. In thismanner, the spinal implant 4100 can be repositioned in a lateraldirection, as indicated by the arrow. Once in the desired position, theexpandable member is reexpanded to the second condition as describedabove. Finally, as shown in FIG. 44, the expansion tool 4130 is removedfrom the valve 4132.

FIG. 45 is a lateral view of the spinal implant 4100 illustrated inFIGS. 39-44 inserted between adjacent spinous processes S in a secondconfiguration. Although FIG. 45 only shows the proximal retentionportion 4114 of the expandable member 4102, it should be understood thatthe distal retention portion 4116 has characteristics and functionalitysimilar to those described below for proximal retention portion 4114. Asillustrated, the proximal retention portion 4114 has a size S1 that isgreater than the vertical distance D1 between the spinous processes S.In this manner, the proximal retention portion 4114 and the distalretention portion 4116 limit the lateral movement of the spinal implant4100 when in the second configuration, as discussed above.

FIG. 46 is a lateral view of a spinal implant 4200 according to anembodiment of the invention inserted between adjacent spinous processesand in a second configuration. Similar to the spinal implant 4100discussed above, the spinal implant 4200 includes an expandable member4202 and a valve 4232. The expandable member 4202 has a support portion(not shown), a proximal retention portion 4214 and a distal retentionportion (not shown). The expandable member 4202 is repeatablypositionable in a first configuration, a second configuration and/or athird configuration. When in each configuration, the expandable member4202 has an associated volume, as discussed above.

In the illustrated embodiment, the proximal retention portion 4214 ofthe expandable member 4202 has a first radial extension 4236, a secondradial extension 4238 and a third radial extension 4240. As illustrated,the distance S1 between the ends of the radial extensions is greaterthan the vertical distance D1 between the spinous processes S. In thismanner, the proximal retention portion 4214 and the distal retentionportion limit the lateral movement of the spinal implant 4200 when inthe second configuration. In some embodiments, the proximal retentionportion and the distal retention portion can assume a variety ofdifferent shapes.

FIGS. 47 and 48 are front views of a spinal implant 4300 according to anembodiment of the invention in a first configuration and a secondconfiguration, respectively. The spinal implant 4300 includes a proximalexpandable member 4304, a distal expandable member 4306, a supportmember 4308, a sensor 4312 and a valve 4332. The support member 4308 hasan inner area (not shown) and an outer surface 4310. The outer surface4310 is configured to contact the spinous processes (not shown). In someembodiments, the support member 4308 distracts the adjacent spinousprocesses. In other embodiments, the support member 4308 does notdistract the adjacent spinous processes. In yet other embodiments, theengagement of the spinous processes by the support member 4308 is notcontinuous, but occurs upon spinal extension.

The support member 4308 has a proximal portion 4324, to which theproximal expandable member 4304 is coupled, and a distal portion 4326,to which the distal expandable member 4306 is coupled. The proximalexpandable member 4304 and the distal expandable member 4306 are eachrepeatably positionable in a first configuration (FIG. 47) and a secondconfiguration (FIG. 48). As described above, the first configurationrepresents a substantially contracted condition in which the proximalexpandable member 4304 and the distal expandable member 4306 each have aminimal volume. When the spinal implant 4300 is in the firstconfiguration, it can be inserted, repositioned and/or removed. In theillustrated embodiment, the proximal expandable member 4304 and thedistal expandable member 4306 are each contained within the inner areaof the support member 4308 when the spinal implant 4300 is in the firstconfiguration. In some embodiments, the proximal expandable member 4304and the distal expandable member 4306 are not contained within thesupport member 4308.

Conversely, the second configuration represents an expanded condition inwhich the proximal expandable member 4304 and the distal expandablemember 4306 each have a large volume. When the spinal implant 4300 is inthe second configuration, the proximal expandable member 4304 and thedistal expandable member 4306 each have a size that is greater than thevertical distance between the spinous processes, as described above. Inthis manner, the proximal expandable member 4304 and the distalexpandable member 4306 engage the spinous processes, thereby limitingthe lateral movement of the spinal implant 4300.

The proximal expandable member 4304 and the distal expandable member4306 are expanded into the second configuration by conveying a fluid(not shown) from an area outside of each expandable member 4304, 4306 toan inner area defined by each expandable member 4304, 4306. The fluid isconveyed through a valve 4332, as described above. In the illustratedembodiment, the inner area of the proximal expandable member 4304, theinner area of the distal expandable member 4306 and the inner area ofthe support member 4308 are in fluid communication with each other toform a single inner area. As such, the fluid can be conveyed to both theinner area of the proximal expandable member 4304 and the inner area ofthe distal expandable member 4306 by a single valve 4332. In someembodiments, the inner areas of the proximal expandable member 4304 andthe distal expandable member 4306 are not in fluid communication. Insuch an arrangement, each expandable member can be independentlytransformed between configurations.

The support member 4308 can be made from any number of biocompatiblematerials, such as, for example, stainless steel, plastic,polyetheretherketone (PEEK), carbon fiber, ultra-high molecular weight(UHMW) polyethylene, and the like. The material of the support member4308 can have a tensile strength similar to or higher than that of bone.In some embodiments, the support member 4308 is substantially rigid. Inother embodiments, the support member 4308 or portions thereof iselastically deformable, thereby allowing it to conform to the shape ofthe spinous processes. In yet other embodiments, the support member 4308includes a radiopaque material, such as bismuth, to facilitate trackingthe position of the spinal implant 4300 during insertion and/orrepositioning.

The proximal expandable member 4304 and the distal expandable member4306 can be made from any number of biocompatible materials, asdiscussed above. The proximal expandable member 4304 and the distalexpandable member 4306 can be coupled to the support member by ansuitable means, such as a biocompatible adhesive.

In the illustrated embodiment, the spinal implant 4300 includes a sensor4312 coupled to the support member 4308. As described above, the sensor4312 can be configured to measure multiple force quantities and/or apressure of the fluid contained within the proximal expandable member4304 and the distal expandable member 4306.

Although the spinal implants 4100, 4200 and 4300 are shown and describedabove as be movable from a retracted configuration to an expandedconfiguration by conveying a fluid to an inner area of an expandablemember, in some embodiments, an implant can be configured to receive anysuitable substance to move from a retracted configuration to an expandedconfiguration. For example, in some embodiments, an implant can includean expandable portion configured to receive a mixture of solid particlescontained within a carrier fluid (e.g., a slurry). In other embodiments,an implant can include an expandable portion configured to be filledsolely with solid particles to move from a retracted configuration to anexpanded configuration. In this manner, the solid particles can form asubstrate within the expandable portion that is incompressible and/ormore rigid than a liquid or gas.

The solid particles can be of any suitable size and/or shape. In someembodiments, for example, the solid particles can be approximatelyspherical particles having a diameter of between 0.010 mm and 0.100 mm.In other embodiments, the solid particles can include one or more flatsurfaces. In yet other embodiments, the solid particles can beirregularly shaped.

The solid particles can be constructed from any suitable biocompatiblematerial, such as, for example, PET, Nylons, cross-linked Polyethylene,Polyurethanes, and PVC. In some embodiments, the solid particles can besubstantially inelastic, thereby forming a low-compliant substratewithin the expandable portion of the implant. In other embodiments, thesolid particles can have a higher elasticity, thereby forming ahigh-compliant filler within the expandable portion of the implant. Inyet other embodiments, the solid particles can be constructed from acombination of materials such that the characteristics of the fillerwithin the expandable portion of the implant can vary spatially.

Similarly, in some embodiments, the solid particles can be constructedfrom a material having a high rigidity (i.e., a high shear modulus). Inthis manner, the solid particles can form a substrate within theexpandable portion that has a high resistance to deformation whenexposed to a shear stress. In other embodiments, the solid particles canbe constructed from a material having a low rigidity. In suchembodiments, for example, the solid particles can form a substrate withthe expandable portion that can deform when compressed during extensionof the spinal column.

In some embodiments, the materials from which the solid particles andthe expandable portion are constructed can be selected cooperativelysuch that the implant, when filled, has suitable strength, rigidity,elasticity and the like. For example, in some embodiments, an implantincludes an expandable portion constructed from a low-compliant materialthat is configured to be expanded by flexible solid particles. In otherembodiments, an implant includes an expandable portion constructed froma low-compliant material that is configured to be expanded by rigidsolid particles. In yet other embodiments, an implant includes anexpandable portion constructed from a high-compliant material that isconfigured to be expanded by flexible solid particles. In yet otherembodiments, an implant includes an expandable portion constructed froma high-compliant material that is configured to be expanded by rigidsolid particles.

In some embodiments, the solid particles and/or mixture of solidparticles and carrier fluid can be conveyed into and/or removed from theexpandable portion of the implant by an expansion tool and via a valve,as described above. In other embodiments, the solid particles and/ormixture of solid particles and carrier fluid can be removed from theexpandable portion of the implant by puncturing the expandable portionand applying a vacuum to withdraw the solid particles and/or mixture ofsolid particles and carrier fluid. In yet other embodiments, the solidparticles and/or mixture of solid particles and carrier fluid can beremoved from the expandable portion of the implant by puncturing theexpandable portion and applying a pressure against an outer portion ofthe expandable portion to cause the solid particles and/or mixture ofsolid particles and carrier fluid to be expelled within the body.

In some embodiments, the solid particles can be configured to absorbliquid to expand the expandable portion of an implant. For example, insome embodiments, an expandable portion of an implant can include solidparticles constructed from a hydrogel. When the implant is disposedbetween adjacent spinous processes, a liquid can be conveyed to theexpandable portion of the implant, which is then absorbed by thehydrogel particles. Accordingly, the size of the hydrogel particles willincrease, thereby expanding the expandable portion of the implant.

Similarly, in some embodiments, a kit can include an implant having anexpandable portion, multiple sets of solid particles, and multipledifferent liquids. The different sets of solid particles can havedifferent characteristics, such as, for example, a size, a shape, and/oran absorption coefficient. Similarly, the different liquids can havedifferent characteristics, such as, for example, viscosity, densityand/or an absorption coefficient. In this manner, a user can select aparticular set of particles for inclusion in the expandable portion ofthe implant and a particular liquid for use in expanding the solidparticles.

FIGS. 49 and 50 are schematic illustrations of a posterior view of amedical device 3000 according to an embodiment of the invention disposedbetween two adjacent spinous processes S in a first configuration and asecond configuration, respectively. The medical device 3000 includes asupport member 3002, a proximal retention member 3010 and a distalretention member 3012. The support member 3002 has a proximal portion3004 and a distal portion 3006, and is configured to be disposed betweenthe spinous processes S to prevent over-extension/compression of thespinous processes S. In some embodiments, the support member 3002distracts the adjacent spinous processes S. In other embodiments, thesupport member 3002 does not distract the adjacent spinous processes S.

The proximal retention member 3010 has a first configuration in which itis substantially disposed within the proximal portion 3004 of thesupport member 3002, as illustrated in FIG. 49. Similarly, the distalretention member 3012 has a first configuration in which it issubstantially disposed within the distal portion 3006 of the supportmember 3002. When the proximal retention member 3010 and the distalretention member 3012 are each in their respective first configuration,the medical device 3000 can be inserted between the adjacent spinousprocesses S.

The proximal retention member 3010 can be moved from the firstconfiguration to a second configuration in which a portion of it isdisposed outside of the support member 3002, as illustrated in FIG. 50.Similarly, the distal retention member 3012 can be moved from the firstconfiguration to a second configuration. When each is in theirrespective second configuration, the proximal retention member 3010 andthe distal retention member 3012 limit lateral movement of the supportmember 3002 with respect to the spinous processes S by contacting thespinous processes S (i.e., either directly or through surroundingtissue). For purposes of clarity, the tissue surrounding the spinousprocesses S is not illustrated.

In use, the adjacent spinous processes S can be distracted prior toinserting the medical device 3000 into the patient. When the spinousprocesses S are distracted, a trocar (not shown in FIG. 49 or 50) can beused to define an access passageway (not shown in FIGS. 49 and 50) forthe medical device 3000. In some embodiments, the trocar can be used todefine the passage as well as to distract the spinous processes S.

Once an access passageway is defined, the medical device 3000 isinserted percutaneously and advanced, distal portion 3006 first, betweenthe spinous processes S. The medical device 3000 can be inserted fromthe side of the spinous processes S (i.e., a posterior-lateralapproach). The use of a curved shaft assists in the use of a lateralapproach to the spinous processes S. Once the medical device 3000 is inplace between the spinous processes S, the proximal retention member3010 and the distal retention member 3012 are moved to their secondconfigurations, either serially or simultaneously. In this manner,lateral movement of the support member 3002 with respect to the spinousprocesses S is limited.

When it is desirable to change the position of the medical device 3000,the proximal retention member 3010 and the distal retention member 3012are moved back to their first configurations, thereby allowing thesupport member 3002 to be moved laterally. Once the support member 3002is repositioned, the medical device 3000 can be returned to the secondconfiguration. Similarly, when it is desirable to remove the medicaldevice 3000, proximal retention member 3010 and the distal retentionmember 3012 are moved to their first configurations, thereby allowingthe support member 3002 to be removed.

In some embodiments, the medical device 3000 is inserted percutaneously(i.e., through an opening in the skin) and in a minimally-invasivemanner. For example, as discussed in detail herein, the overall sizes ofportions of the medical device 3000 can be increased by moving theproximal retention member 3010 and the distal retention member 3012 totheir respective second configurations after the medical device 3000 isinserted between the adjacent spinous processes S. When in the expandedsecond configuration, the sizes of portions of the medical device 3000can be greater than the size of the opening. For example, the size ofthe opening/incision in the skin can be between 3 millimeters in lengthand 25 millimeters in length across the opening. In some embodiments,the size of the medical device 3000 in the expanded second configurationis between 3 and 25 millimeters across the opening.

FIGS. 51-56 illustrate a spinal implant 3100 according to an embodimentof the invention. FIGS. 51 and 52 are perspective views of the spinalimplant 3100 in a first configuration and a second configuration,respectively. The spinal implant 3100 includes a support member 3102, aproximal retention member 3110 and a distal retention member 3112. Thesupport member 3102 is positioned between adjacent spinous processes S,as illustrated in FIGS. 53 and 54. As shown in FIGS. 51 and 52, theproximal retention member 3110 and the distal retention member 3112 areeach repeatably positionable in a first configuration in which they aresubstantially disposed within the support member 3102 (FIG. 51), and asecond configuration in which a portion of each retention member 3110,3112 is disposed outside of the support member 3102 (FIG. 52). When thespinal implant 3100 is in the first configuration, it can be insertedbetween the adjacent spinous processes S, repositioned between theadjacent spinous processes and/or removed from the patient. When thespinal implant 3100 is in the second configuration, its lateral movementis limited, thereby allowing the desired position of the support member3102 to be maintained.

In some embodiments, the support member 3102 distracts the adjacentspinous processes S. In other embodiments, the support member 3102 doesnot distract the adjacent spinous processes S. In yet other embodiments,the engagement of the spinous processes S by the support member 3102 isnot continuous, but occurs upon spinal extension.

The support member 3102 can be made from any number of biocompatiblematerials, such as, for example, stainless steel, plastic,polyetheretherketone (PEEK), carbon fiber, ultra-high molecular weight(UHMW) polyethylene, and the like. The material of the support member3102 can have a tensile strength similar to or higher than that of bone.In some embodiments, the support member 3102 is substantially rigid. Inother embodiments, the support member 3102 or portions thereof iselastically deformable, thereby allowing it to conform to the shape ofthe spinous processes. In yet other embodiments, the support member 3102includes a radiopaque material, such as bismuth, to facilitate trackingthe position of the spinal implant 3100 during insertion and/orrepositioning.

In the illustrated embodiment, the spinal implant 3100 includes a sensor3124 coupled to the support member 3102. In some embodiments, the sensor3124 is a strain gauge sensor that measures a force applied to thesupport member 3102. In some embodiments, the sensor 3124 can includemultiple strain gauges to facilitate measuring multiple forcequantities, such as a compressive force and/or a bending moment. Inother embodiments, the sensor 3124 is a variable capacitance typepressure sensor configured to measure a force and/or a pressure appliedto the support member 3102. In yet other embodiments, the sensor 3124 isa piezoelectric sensor that measures a force and/or a pressure appliedto the support member 3102. In still other embodiments, the spinalimplant 3100 can include multiple sensors located at various locationsto provide a spatial profile of the force and/or pressure applied to thesupport member 3102. In this manner, a practitioner can detect changesin the patient's condition, such those that may result in a loosening ofthe spinal implant.

In some embodiments, the sensor 3124 can be remotely controlled by anexternal induction device. For example, an external radio frequency (RF)transmitter (not shown) can be used to supply power to and communicatewith the sensor 3124. In other embodiments, an external acoustic signaltransmitter (not shown) can be used to supply power to and communicatewith the sensor 3124. In such an arrangement, for example, the sensorcan include a pressure sensor, of the types described above, formeasuring a pressure; an acoustic transducers, and an energy storagedevice. The acoustic transducer converts energy between electricalenergy and acoustic energy. The energy storage device stores theelectrical energy converted by the acoustic transducer and supplies theelectrical energy to support the operation of the pressure sensor. Inthis manner, acoustic energy from an external source can be received andconverted into electrical energy used to power the pressure sensor.Similarly, an electrical signal output from the pressure sensor can beconverted into acoustic energy and transmitted to an external source.

The support member 3102 includes a sidewall 3108 that defines an innerarea 3120 and multiple openings 3114 that connect the inner area 3120 toan area outside of the support member 3102. When the spinal implant 3100is in the first configuration, the proximal retention member 3110 andthe distal retention member 3112 are substantially disposed within theinner area 3120 of the support member 3102, as shown in FIG. 51. Whenthe spinal implant 3100 is in the second configuration, a portion ofeach of the proximal retention member 3110 and the distal retentionmember 3112 extends through the openings 3114 to an area outside of thesupport member 3102. In the second configuration, the proximal retentionmember 3110 and the distal retention member 3112 engage the adjacentspinous processes, thereby limiting lateral movement of the spinalimplant 3100.

The proximal retention member 3110 includes a first elongate member 3130and a second elongate member 3132. Similarly, the distal retentionmember 3112 includes a first elongate member 3131 and a second elongatemember 3133. As illustrated in FIG. 56, which shows is a cross-sectionalplan view of the proximal portion 3104 of the support member 3102, thefirst elongate member 3130 is slidably disposed within a pocket 3134defined by the second elongate member 3132. A biasing member 3136, suchas a spring or an elastic member, is disposed within the pocket 3134 andis coupled to the first elongate member 3130 and the second elongatemember 3132. In this manner, the retention members can be biased in thesecond configuration. In other embodiments, the biasing member 3136 canbe configured to bias the retention members in the first configuration.In yet other embodiments, the retention members do not include a biasingmember, but instead use other mechanisms to retain a desiredconfiguration. Such mechanisms can include, for example, mating tabs andslots configured to lockably engage when the retention members are in adesired configuration.

In use, the spinal implant 3100 is positioned in the first configurationduring insertion, removal or repositioning. As discussed above, thespinal implant 3100 is inserted percutaneously between adjacent spinousprocesses. The distal portion 3106 of the support member 3102 isinserted first and is moved past the spinous processes until the supportmember 3102 is positioned between the spinous processes. The supportmember 3102 can be sized to account for ligaments and tissue surroundingthe spinous processes S. In some embodiments, the support member 3102contacts the spinous processes between which it is positioned during aportion of the range of motion of the spinous processes S. In someembodiments, the support member 3102 of spinal implant 3100 is a fixedsize and is not compressible or expandable. In yet other embodiments,the support member 3102 can compress to conform to the shape of thespinous processes S. Similarly, in some embodiments, the proximalretention member 3110 and the distal retention member 3112 aresubstantially rigid. In other embodiments, the retention members orportions thereof are elastically deformable, thereby allowing them toconform to the shape of the spinous processes.

In the illustrated embodiment, the spinal implant 3100 is held in thefirst configuration by an insertion tool (not shown) that overcomes theforce exerted by the biasing member 3136, thereby disposing a portion ofthe first elongate member 3130 within the pocket 3134 of the secondelongate member 3132. In this manner, the spinal implant 3100 can berepeatedly moved from the first configuration to the secondconfiguration, thereby allowing it to be repositioned and/or removedpercutaneously. As illustrated in FIG. 55, the first elongate member3130 and the second elongate member 3132 each include notches 3138configured to receive a portion of the insertion tool. When theinsertion tool is released, the biasing member 3136 is free to extend,thereby displacing a portion of the first elongate member 3130 out ofthe pocket 3134 of the second elongate member 3132. In this manner,portions of both the first elongate member 3130 and the second elongatemember 3132 are extended through the adjacent openings 3114 and to anarea outside of the support member 3102. In some embodiments, theproximal retention member 3110 and the distal retention member 3112 aretransitioned between their respective first and second configurationssimultaneously. In other embodiments, the proximal retention member 3110and the distal retention member 3112 are transitioned between theirfirst and second configurations serially.

As illustrated, the first elongate member 3130 and the second elongatemember 3132 each include one or more tabs 3140 that engage the side wall3108 of the support member 3102 when in the second configuration,thereby ensuring that the first and second elongate members remaincoupled to each other and that portions of the first and second elongatemembers remain suitably disposed within the support member 3102. Inother embodiments, the first elongate member 3130 and the secondelongate member 3132 are coupled to each other by other suitablemechanisms, such as mating tabs and slots configured to engage when theretention member reaches a predetermined limit of extension.

FIGS. 57-59 are cross-sectional views of a spinal implant 3200 accordingto an embodiment of the invention. FIG. 57 illustrates a cross-sectionalfront view of the spinal implant 3200 in a second configuration, whileFIGS. 58 and 59 illustrate a cross-sectional plan view of the spinalimplant 3200 in the second configuration and a first configuration,respectively. The illustrated spinal implant 3200 includes a supportmember 3202, a retention member 3210 and a rotating member 3250.Although shown and described as including only a single retention member3210, some embodiments can include one or more additional retentionmembers having characteristics and functionality similar to thosedescribed for the retention member 3210.

As shown in FIGS. 58 and 59, the retention member 3210 is repeatablypositionable in a first configuration in which it is substantiallydisposed within the support member 3202, and a second configuration inwhich a portion the retention member 3210 is disposed outside of thesupport member 3102. When the spinal implant 3200 is in the firstconfiguration, it can be inserted between adjacent spinous processes,repositioned between adjacent spinous processes and/or removed from thepatient. When the spinal implant 3200 is in the second configuration,its lateral movement is limited, thereby allowing the desired positionof the support member 3202 to be maintained.

The support member 3202 includes a sidewall 3208 that defines an innerarea 3220 and multiple openings 3214 that connect the inner area 3220 toan area outside of the support member 3202. When the spinal implant 3200is in the first configuration, the retention member 3210 issubstantially disposed within the inner area 3220 of the support member3202, as shown in FIG. 59. When the spinal implant 3200 is in the secondconfiguration, a portion of the proximal retention member 3210 extendsthrough the openings 3214 to an area outside of the support member 3202.In the second configuration, the retention member 3210 is disposedadjacent the spinous processes, thereby limiting lateral movement of thespinal implant 3200.

The retention member 3210 includes an elongate member 3228 having twoend portions 3244, a central portion 3242, and a longitudinal axis L1(shown in FIG. 57). A portion of the elongate member 3228 is flexiblesuch that it can be wound along the rotating member 3250, as describedbelow. In some embodiments, the elongate member 3228 is monolithicallyformed such that it is flexible enough to be wound along the rotatingmember 3250 yet rigid enough to limit lateral movement of the supportmember 3202 when positioned in the second configuration. In otherembodiments, the elongate member 3228 includes separate components thatare coupled together to form the elongate member 3228. For example, thecentral portion 3242 of the elongate member 3228 can be a distinctcomponent having a greater amount of flexibility, while the end portions3244 can be distinct components having a greater amount of rigidity.

In the illustrated embodiment, elongate member 3228 has one or more tabs3240 that engage the side wall 3208 of the support member 3202 when inthe second configuration, thereby ensuring that the elongate member 3228does not freely extend entirely outside of the support member 3202. Inother embodiments, a portion of the elongate member 3228 is retainedwithin the support member 3202 by other suitable mechanisms. Forexample, the width of the central portion 3242 of the elongate member3228 can be greater than the width of the openings 3214, therebyensuring that a portion of the elongate member 3228 will remain withinthe support member 3202.

The rotating member 3250 defines an outer surface 3252 and a slot 3254through which the elongate member 3228 is disposed. The rotating member3250 has a longitudinal axis L2 (shown in FIG. 57) about which itrotates. As illustrated in FIG. 59, as the rotating member 3250 rotates,the elongate member 3228 is wound along the outer surface 3252 of therotating member 3250. This causes the elongate member 3228 to move alongits longitudinal axis L1, thereby causing the end portions 3244 of theelongate member 3228 to be retracted inwardly through the openings 3214.In this manner, the retention member 3210 can be repeatedly transitionedbetween the first configuration and the second configuration.

In some embodiments, the rotating member 3250 is rotated using aninsertion tool (not shown) that includes a ratchet mechanism. Theinsertion tool can rotate the rotating member 3250 in a number ofdifferent ways, such as, for example, manually, pneumatically orelectronically.

FIGS. 60-63 are cross-sectional views of a spinal implant 3300 accordingto an embodiment of the invention. FIG. 60 illustrates a cross-sectionalfront view of the spinal implant 3300 in a second configuration, whileFIGS. 61-63 illustrate a cross-sectional plan view of the spinal implant3300 in the second configuration, a first configuration, and a thirdconfiguration, respectively. The illustrated spinal implant 3300includes a support member 3302 and a retention member 3310. Althoughshown and described as including only a single retention member 3310,some embodiments can include one or more additional retention membershaving characteristics and functionality similar to those described forthe retention member 3310.

As shown in FIGS. 61-63, the retention member 3310 is repeatablypositionable in a first configuration, a second configuration and athird configuration. A portion the retention member 3310 is disposedoutside of the support member 3302 when positioned in the secondconfiguration. The retention member 3310 is substantially disposedwithin the support member 3202 when positioned in each of the first andthird configurations. As illustrated in FIGS. 62 and 63, the orientationof the retention member 3310 differs between the first and thirdconfigurations. In this manner, the position of the spinal implant 3300can be positioned appropriately depending on the direction in which itis being moved. For example, the spinal implant 3300 may be positionedin the first configuration to facilitate lateral movement of the supportmember 3302 in a distal direction, such as during insertion. Conversely,the spinal implant 3300 may be positioned in the third configuration tofacilitate lateral movement of the support member 3302 in a proximaldirection, such as during removal.

The support member 3302 includes a sidewall 3308 that defines an innerarea 3320 and multiple openings 3314 that connect the inner area 3320 toan area outside of the support member 3302. When the spinal implant 3300is in the second configuration, a portion of the proximal retentionmember 3310 extends through the openings 3314 to an area outside of thesupport member 3302.

The retention member 3310 includes a first elongate member 3330, asecond elongate member 3332, and a hinge 3360 having a longitudinal axisL2 (shown in FIG. 60). Each of the first elongate member 3330 and thesecond elongate member 3332 has a distal end portion 3344 that extendsthrough the openings 3314 when the spinal implant 3300 is in the secondconfiguration and a proximal end portion 3346 that is pivotally coupledto the hinge 3360. In use, the hinge 3360 moves in a direction normal toits longitudinal axis L2, as indicated by the arrows in FIGS. 62 and 63.The motion of the hinge is guided by a slot 3362 defined by the sidewall 3308 of the support member 3302. The movement of the hinge 3360allows the each of the first elongate member 3330 and the secondelongate member 3332 to rotate about the longitudinal axis L2 of thehinge 3360, thereby positioning the distal end portion 3344 of eachelongate member substantially within the inner area 3320 of the supportmember 3302.

In some embodiments, the slot 3362 includes detents or any othersuitable mechanism (not shown) to maintain the hinge 3360 in the desiredposition. In other embodiments the hinge 3360 includes a biasing member(not shown) configured to bias the hinge 3360 in one of the first,second, or third configurations. In yet other embodiments, the elongatemembers include other suitable mechanisms to retain the retention memberin a desired configuration. Such mechanisms can include, for example,mating tabs and slots configured to lockably engage when the elongatemembers are in a desired configuration.

In some embodiments, the first elongate member 3330 and the secondelongate member 3332 are monolithically formed of a substantially rigidmaterial. In other embodiments, the first elongate member 3330 and thesecond elongate member 3332 include separate components having differentmaterial properties. For example, the distal end portion 3344 can beformed from a material having a greater amount of flexibility, while theproximal end portion 3346 can be formed from a substantially rigidmaterial. In this manner, movement of the spinal implant 3300 is notrestricted when a portion of the distal end portion 3344 protrudes fromthe openings 3314 in either the first configuration or the thirdconfiguration.

FIGS. 64 and 65 are cross-sectional front views of a spinal implant 3400according to an embodiment of the invention. The illustrated spinalimplant 3400 includes a support member 3402, a retention member 3410 anda rotating member 3450. As shown in FIGS. 64 and 65, the retentionmember 3410 is repeatably positionable in a first configuration in whichit is substantially disposed within the support member 3402, and asecond configuration in which a portion the retention member 3410 isdisposed outside of the support member 3402. Although shown anddescribed as including only a single retention member 3410, someembodiments include one or more additional retention members havingcharacteristics and functionality similar to those described for theretention member 3410.

The support member 3402 includes a sidewall 3408 that defines an innerarea 3420 and multiple openings 3414 that connect the inner area 3420 toan area outside of the support member 3402. When the spinal implant 3400is in the second configuration, a portion of the proximal retentionmember 3410 extends through the openings 3414 to an area outside of thesupport member 3402.

The retention member 3410 includes a first elongate member 3430 and asecond elongate member 3432, each having a distal end portion 3444 thatextends through the openings 3414 when the spinal implant 3400 is in thesecond configuration, a proximal end portion 3446, and a longitudinalaxis L1. As illustrated, the proximal end portions 3346 are coupled bytwo elastic members 3468, such as a spring or an elastic band. In someembodiments, the proximal end portions 3346 are coupled by a singleelastic member. In other embodiments, the proximal end portions 3346 areindirectly coupled via the rotating member 3450. In such an arrangement,for example, a biasing member can be placed between the sidewall of thesupport member and each elongate member, thereby biasing each elongatemember against the rotating member.

In the illustrated embodiment, the elongate members each include one ormore tabs 3440 that engage the side wall 3408 of the support member 3402when in the second configuration, thereby ensuring that the elongatemembers 3430, 3432 does not freely extend entirely outside of thesupport member 3402. In other embodiments, the elongate members do notinclude tabs, but are retained within the support member 3402 solely bythe elastic members 3468. In yet other embodiments, the width of aportion of the elongate members can be greater than the width of theopenings 3414, thereby ensuring that the elongate members will remainwithin the support member 3402.

The rotating member 3450 defines an outer surface 3452 having aneccentric shape and includes a longitudinal axis (not shown) about whichit rotates. As illustrated in FIGS. 64 and 65, as the rotating member3450 rotates about its longitudinal axis, a portion of the proximal endportion 3346 of the first elongate member 3430 and the second elongatemember 3432 engage the outer surface 3452 of the rotating member 3250.This causes the first elongate member 3430 and the second elongatemember 3432 to move along their respective longitudinal axes L1, therebycausing the end portions 3444 of each elongate member to be extendedoutwardly through the openings 3414, as indicated by the arrows in FIG.64. In this manner, the retention member 3410 can be repeatedlytransitioned between the first configuration and the secondconfiguration.

In some embodiments, the rotating member 3450 is rotated using aninsertion tool (not shown) that includes a ratchet mechanism. Theinsertion tool can rotate the rotating member 3450 in a number ofdifferent ways, such as, for example, manually, pneumatically orelectronically.

FIGS. 66 and 67 illustrate a spinal implant 3500 according to anembodiment of the invention. FIG. 66 is a cross-sectional front view ofthe spinal implant 3500 in a second configuration. FIG. 67 is across-sectional plan view of the spinal implant 3500 taken along sectionA-A. The spinal implant 3500 includes a support member 3502 and aretention member 3510. Although only shown as being in a second orexpanded configuration, it is understood from the previous descriptionsthat the retention member 3510 is repeatably positionable in a firstconfiguration in which it is substantially disposed within the supportmember 3502, and the second configuration in which a portion theretention member 3510 is disposed outside of the support member 3502.

As illustrated, the retention member 3510 includes a first elongatemember 3530 and a second elongate member 3532. The first elongate member3530 is slidably disposed within a pocket 3534 defined by the secondelongate member 3532. The first elongate member 3530 and the secondelongate member 3532 each include one or more tabs 3540 that are coupledto the side wall 3508 of the support member 3502 by one or more biasingmembers 3536. In this manner, the retention member 3510 is biased in thefirst or retracted configuration. In other embodiments, the biasingmembers 3536 can be configured to bias the retention member 3510 in thesecond configuration. In yet other embodiments, the retention member3510 is not retained by a biasing member 3536, but rather uses othersuitable mechanisms to retain the desired configuration.

In use, the retention member 3510 is transitioned from the firstconfiguration to the second configuration by supplying a pressurizedfluid (not shown) to the pocket 3534 via valve 3570. The pressureexerted by the fluid on each of the first elongate member 3530 and thesecond elongate member 3532 overcomes the force exerted by the biasingmembers 3536, thereby causing a portion the first elongate member 3530to extend outwardly from the pocket 3534 of the second elongate member3132, thereby allowing a portion of each elongate member to extendthrough the adjacent openings 3514 and to an area outside of the supportmember 3502. Similarly, the retention member 3510 is transitioned fromthe second configuration to the first configuration by opening the valve3570 and relieving the pressure within the pocket 3534. In this manner,the spinal implant 3500 can be repeatedly moved from the firstconfiguration to the second configuration, thereby allowing it to berepositioned and/or removed percutaneously.

FIGS. 68 and 69 illustrate perspective views of a spinal implant 3600according to an embodiment of the invention. The spinal implant 3600includes a support member 3602, a proximal retention member 3610, adistal retention member 3612, and an elastic member 3668. The supportmember 3602 defines a longitudinal axis L1 and has a sidewall 3608 thatdefines an inner area 3620 and has an outer surface 3616. As illustratedin FIG. 69, the outer surface 3616 defines an area A normal to thelongitudinal axis L1. As shown, the proximal retention member 3610 andthe distal retention member 3612 are each repeatably positionable in afirst configuration in which they are substantially disposed within thearea A (FIG. 69), and a second configuration in which a portion of eachretention member 3610, 3612 is disposed outside of the area A (FIG. 68).

As illustrated, the proximal retention member 3610 and the distalretention member 3612 are coupled by the elastic member 3668, a portionof which is disposed within the inner area 3620 of the support member3602. In the illustrated embodiment, the elastic member 3668 has asidewall 3674 that defines a lumen 3676. In other embodiments, theelastic member can be, for example, a spring, an elastic band, or anyother suitable device for elastically coupling the proximal retentionmember 3610 and the distal retention member 3612.

The proximal retention member 3610 includes a first elongate member 3630and a second elongate member 3632, each of which are pivotally coupledto a connection member 3678 by a hinge 3660. Similarly, the distalretention member 3612 includes a first elongate member 3631 and a secondelongate member 3633 each of which are pivotally coupled to a connectionmember 3678 by a hinge 3660.

As illustrated in FIG. 68, when the spinal implant 3600 is in the secondconfiguration, the elastic member 3668 exerts a biasing force on eachconnection member 3678, thereby causing the connection members 3678 toremain adjacent to the support member 3602. In this configuration, thefirst elongate member 3630 and the second elongate member 3632 are fullyextended. The spinal implant 3600 is transitioned from the secondconfiguration to the first configuration by stretching the elasticmember 3668, which allows the connection members 3678 to be disposedapart from the support member 3602, thereby allowing the elongatemembers to move within the area A, as illustrated in FIG. 69. Thesupport member 3602 includes slots 3672 in which the end portion of eachelongate member can be disposed to maintain the spinal implant 3600 inthe first configuration.

The elastic member 3668 can be stretched by an insertion tool (notshown), a portion of which can be configured to be disposed within thelumen 3676 of the elastic member 3668. For example, a first portion ofan insertion tool can engage the connection member 3678 of the proximalretention member 3610 while a second portion of the insertion tool canengage the connection member 3678 of the distal retention member 3612.The tool can then be configured to exert an outward force on each of theconnection members 3678, thereby stretching the elastic member 3668 andallowing the spinal implant to transition from the second configurationto the first configuration.

While the spinal implants are shown and described above as having one ormore retention members that extend substantially symmetrically from asupport member when in a second configuration, in some embodiments, aspinal implant includes a retention member that extends asymmetricallyfrom a support member when in a second configuration. For example, FIGS.70-74 illustrate a spinal implant 3700 according to an embodiment of theinvention that includes a proximal retention member 3710 and a distalretention member 3712 that extend asymmetrically from a support member3702. As shown in FIGS. 70-74, the proximal retention member 3710 andthe distal retention member 3712 are each repeatably positionable in afirst configuration in which they are substantially disposed within thesupport member 3702, and a second configuration in which a portion eachis disposed outside of the support member 3702.

The support member 3702 includes a sidewall 3708 that defines an innerarea 3720 and two openings 3714 that connect the inner area 3720 to anarea outside of the support member 3702. When the spinal implant 3700 isin the second configuration, a portion of the proximal retention member3710 and a portion of the distal retention member 3712 extend throughthe openings 3714 to an area outside of the support member 3702.

In the illustrated embodiment, the proximal retention member 3710 andthe distal retention member 3712 each include a first end portion 3746and a second end portion 3744. The first end portions 3746 of theproximal retention member 3710 and the distal retention member 3712 arecoupled by a connecting member 3782 that has a longitudinal axis L1(shown in FIG. 74). In some embodiments, the connecting member 3782, theproximal retention member 3710 and the distal retention member 3712 areseparate components that are coupled together to form the illustratedstructure. In other embodiments, the connecting member 3782, theproximal retention member 3710 and the distal retention member 3712 aremonolithically formed.

The connecting member 3782 defines a longitudinal axis L1, about whichit rotates. As illustrated, as the connecting member 3782 rotates, theproximal retention member 3710 and the distal retention member 3712 alsorotate, thereby causing the end portions 3744 of the proximal retentionmember 3710 and the distal retention member 3712 to extend outwardlythrough the openings 3714. In this manner, the retention member 3210 canbe repeatedly transitioned between the first configuration and thesecond configuration.

In some embodiments, the connecting member 3782 is rotated using aninsertion tool (not shown) that includes a ratchet mechanism. Theinsertion tool can rotate the connecting member 3782 in a number ofdifferent ways, such as, for example, manually, pneumatically orelectronically.

As described herein, in some embodiments, the spinal implants shown anddescribed above can be inserted between adjacent spinous processespercutaneously using a posterior-lateral approach. FIGS. 75 and 76 showan implant 8100 and a portion of an insertion tool 8500 being insertedinto a body B using a posterior-lateral approach according to anembodiment of the invention. The body B includes spinous processesSP1-SP4, which define a mid-line axis L_(M). A lateral axis L_(L) isdefined substantially normal to the mid-line axis L_(M).

To position the implant 8100 between adjacent spinous processes SP2 andSP3, a lateral incision I having a length Y2 is made a distance X fromthe mid-line axis L_(M). The length Y2 and the distance X can beselected to allow the implant to be inserted percutaneously in aminimally-invasive manner. In some embodiments, the distance X can be,for example, between 25 mm and 100 mm. In some embodiments, the incisionI has a length Y2 that is no greater than the distance Y1 between theadjacent spinous processes, such as, for example, SP2 and SP3. In someembodiments, for example, the length Y2 is no greater than 15 mm and thedistance Y1 is between 20 mm and 25 mm. In other embodiments, the lengthY2 can exceed the distance Y1 between the adjacent spinous processes SP2and SP3. In some embodiments, for example, the length Y2 can be as muchas 50 mm.

A distraction tool (not shown in FIGS. 75 and 76) is then insertedthrough the incision I and is used to define the passageway P from theincision I to the adjacent spinous processes SP2 and SP3. Thedistraction tool can also distract the adjacent spinous processes SP2and SP3 to define the desired space between, as described above. Thedistraction tool can be any suitable distraction tool of the type shownand described herein.

The insertion tool 8500 including the implant 8100 is then insertedthrough the incision I and via the passageway P to the space between theadjacent spinous processes SP2 and SP3. The implant 8100 is thendisposed between the adjacent spinous processes SP2 and SP3 in anysuitable manner, as described above. For example, in some embodiments,the implant 8100 can include one or more expandable portions that areadjacent to and/or engage portions of the spinous processes SP2 and/orSP3 to limit at least a lateral movement of the implant 8100.

As shown in FIGS. 75 and 76, during the insertion operation, theinsertion tool 8500 is positioned such that when the implant 8100 isdisposed between the adjacent spinous processes SP2 and SP3, the implant8100 is substantially aligned with the lateral axis L_(L). Said anotherway, during insertion, the insertion tool 8500 is positioned such thatthe longitudinal axis (not shown) of the implant 8100 is substantiallycoaxial with the lateral axis L_(L). As described in more detail herein,the insertion tool 8500 is configured to ensure that the implant 8100 isaligned with the lateral axis L_(L) during insertion.

As shown in FIGS. 77 and 78, the insertion tool 8500, which can besimilar to the insertion tools 1500 and 7500 shown and described above,includes a curved portion 8520 and an implant support portion 8530. Theinsertion tool 8500 defines a center line CL. As shown in FIGS. 77 and78, which show a side view and a top plan view, respectively, of theinsertion tool 8500, the center line CL of the curved portion 8520defines a radius of curvature R1 about an axis A1 that is substantiallynormal to the center line CL. The radius of curvature R1 can be anyvalue suitable to define and/or proceed along the passageway P such thatthe implant 8100 and/or a portion of the center line CL is aligned withthe lateral axis L_(L) during insertion. Moreover, the radius ofcurvature R1 can be selected to blend with the adjacent portions of theinsertion tool 8500 to ensure that the surface of the insertion tool8500 is continuous.

In some embodiments, for example, an insertion tool 8500 can have asmall radius of curvature R1 (e.g., 20 mm to 50 mm), which correspondsto a relatively sharp curve. Such an embodiment can be appropriate, forexample, when the distance X between the incision I and the mid-lineaxis L_(M) is relatively small (e.g. 20 mm), requiring that passageway Phave a relatively sharp curve to ensure that the implant 8100 isproperly aligned. In other embodiments, for example, an insertion tool8500 can have a large radius of curvature R1 (e.g., greater than 300mm), which corresponds to less curvature. Such an embodiment can beappropriate, for example, when the distance X between the incision I andthe mid-line axis L_(M) is relatively great (e.g. greater than 50 mm).In yet other embodiments, an insertion tool 8500 can have a radius ofcurvature R1 that is between 50 mm and 300 mm. In some embodiments, forexample, an insertion tool 8500 can have a radius of approximately 181mm.

Although the insertion tool 8500 is shown and described as having asingle radius of curvature R1, in some embodiments, an insertion toolcan have multiple radii of curvature and/or geometrically complexshapes. For example, FIGS. 79 and 80 show a side view and a top planview of an insertion tool 9500 according to an embodiment of theinvention. The insertion tool 9500 includes a curved portion 9520 and animplant support portion 9530. A center line CL of the curved portion9520 defines a first radius of curvature R1 about a first axis A1 thatis substantially normal to the center line CL. The center line CL of thecurved portion 9520 also defines a second radius of curvature R2 about asecond axis A2 that is substantially parallel to the first axis A1 andsubstantially normal to the center line CL. As described above, theradii of curvature R1 and R2 can be any value suitable to define thepassageway P such that the implant is aligned with the lateral axisL_(L) during insertion. Moreover, as shown in FIG. 79, a portion of theelongate member 9500 is disposed between the first axis A1 and thesecond axis A2. Said another way, the first axis A1 and the second axisA2 are positioned such that the curved portion 9520 forms an “S” shape.

Although the insertion tool 9500 is shown and described as defining axisA1 and axis A2 with insertion tool 9500 therebetween, in otherembodiments, an insertion tool can be on the same side of these axes.Similarly, although the insertion tool 9500 is described as definingaxes A1 and A2 that are substantially parallel to each other, in otherembodiments, an insertion tool can define axes A1 and A2 that are notsubstantially parallel to each other. Said another way, although theinsertion tool 9500 is shown as having a two-dimensional curve, in otherembodiments, an insertion tool can have a three-dimensional curve.

FIGS. 81-84 are schematic illustrations of an implant 22100 according toan embodiment of the invention. FIGS. 81 and 83 are posterior views ofthe implant 22100 in a first configuration and a second configuration,respectively, disposed between a first spinous process SP1 and a secondspinous process SP2 adjacent the first spinous process SP1. FIGS. 82 and84 are lateral views of the implant 22100 in the first configuration andthe second configuration, respectively, disposed between the firstspinous process SP1 and the second spinous process SP2. The implant22100 includes a first member 22102 and a second member 22112 movablycoupled to the first member 22102.

The first member 22102 has a proximal portion 22104, a distal portion22106, a first surface 22116, and a second surface 22117. The firstsurface 22116 of the first member 22102 is substantially parallel to alongitudinal axis L_(A) of the first member 22102. Said another way, thelongitudinal axis L_(A) and a line defined to include a portion of thefirst surface 22116 of the first member 22102 are non-intersecting asthey extend to infinity. Said yet another way, in embodiments in whichthe first surface 22116 of the first member 22102 includes at least aplanar portion, every point along the longitudinal axis L_(A) is spacedapart from the nearest portion of a plane defined to include the planarportion of the first surface 22116 of the first member 22102 by asubstantially equal distance. The longitudinal axis L_(A) can, forexample, pass lengthwise (e.g., from the proximal portion 22104 to thedistal portion 22106) through the centroid of the first member 22102(e.g., the longitudinal axis L_(A) can be a centroidal axis of the firstmember 22102). As shown, when the implant 22100 is disposed between thefirst spinous process SP1 and the second spinous process SP2, thelongitudinal axis L_(A) can be substantially parallel and/or coincidentwith a lateral axis defined by the spinal column.

As shown, at least a portion of the first surface 22116 of the firstmember 22102 is disposed between the first spinous process SP1 and thesecond spinous process SP2. In this manner, the implant 22100 canmaintain a minimal spacing between the adjacent spinous processes SP Iand SP2 during extension of the spinal column (not shown FIGS. 81-84)while allowing flexion of the spinal column. Moreover, in someembodiments, the implant 22100 can distract a prior spacing of theadjacent spinous processes SP1 and SP2.

The second surface 22117 is disposed at the distal portion 22106 of thefirst member 22102 and intersects the longitudinal axis L_(A) at anangle of approximately 90 degrees. Said another way, the second surface22117 of the first member 22102 is substantially normal to the firstsurface 22116 of the first member 22102. Although the second surface22117 of the first member 22102 is shown as intersecting thelongitudinal axis L_(A) of the first member 22102 at an angle ofapproximately 90 degrees, in other embodiments, the second surface ofthe first member can intersect the longitudinal axis of the first memberby any non-zero angle.

The second member 22112 has a first surface 22136 and a second surface22137. The first surface 22136 is substantially parallel to thelongitudinal axis L_(A) of the first member 22102. Said another way, thelongitudinal axis L_(A) and a line defined to include a portion of thefirst surface 22136 of the second member 22112 are non-intersecting asthey extend to infinity. Said yet another way, in embodiments in whichthe first surface 22136 of the second member 22112 includes at least aplanar portion, every point along the longitudinal axis L_(A) is spacedapart from the nearest portion of a plane defined to include the planarportion of the first surface 22136 of the second member 22112 by asubstantially equal distance. Although the first surface 22136 of thesecond member 22112 is shown as being substantially parallel to thelongitudinal axis L_(A) of the first member 22102, in other embodiments,the first surface of the second member can intersect the longitudinalaxis of the first member by any non-zero angle.

The second surface 22137 intersects the longitudinal axis L_(A) at anangle of approximately 90 degrees. Said another way, the second surface22137 of the second member 22112 is substantially parallel to the secondsurface 22117 of the first member 22102, substantially normal to thefirst surface 22136 of the second member 22112, and substantially normalto the first surface 22116 of the first member 22102. Although thesecond surface 22137 of the second member 22112 is shown as intersectingthe longitudinal axis L_(A) of the first member 22102 at an angle ofapproximately 90 degrees, in other embodiments, the second surface ofthe second member can intersect the longitudinal axis of the firstmember by any non-zero angle.

As shown in FIGS. 81 and 83, the second member 22112 is coupled to thedistal portion 22106 of the first member 22102 such that at least aportion of the second surface 22137 of the second member 22112 is incontact with at least a portion of the second surface 22117 of the firstmember 22102. In other embodiments, however, the second member can becoupled to the distal portion of the first member such that the secondsurface of the second member is spaced apart from the second surface ofthe first member 22102.

As shown in FIGS. 82 and 84, the first member 22102 has a firstdimension X₁ along an axis X substantially normal to the longitudinalaxis L_(A) (e.g., a length of the second surface 22117) and a seconddimension Y₁ along an axis Y substantially normal to both thelongitudinal axis L_(A) and the axis X (e.g., a height of the secondsurface 22117). Similarly, the second member 22112 has a first dimensionX₂ along the axis X (e.g., a length of the second surface 22137) and asecond dimension Y₂ along the axis Y (e.g., a height of the secondsurface 22137). The first dimension X₂ of the second member 22112 isgreater than the second dimension Y₁ of the first member 22102 and is nogreater than the first dimension X₁ of the first member 22102. Thesecond dimension Y₂ of the second member 22112 is no greater than thesecond dimension Y₁ of the first member 22102. Said another way, whenthe second member 22112 is in a first position, as shown in FIG. 82, thefootprint of the second member 22112 (e.g., a projected area having thefirst dimension X₂ and the second dimension Y₂) is within the footprintof the first member 22102 (e.g., a projected area having the firstdimension X₁ and the second dimension Y₁).

The second member 22112 is coupled to the first member 22102 such thatthe second member 22112 can rotate relative to the first member 22102about an axis of rotation L_(R) substantially parallel to thelongitudinal axis L_(A). As indicated by the arrows AA in FIGS. 83 and84, the second member 22112 can rotate relative to the first member22102 between a first position (FIGS. 81 and 82) and a second position(FIGS. 83 and 84). When the second member 22112 is in the firstposition, the implant 22100 can be inserted such that at least a portionof the first surface 22116 of the first member 22102 is disposed betweenthe first spinous process SP1 and the second spinous process SP2. Whenthe second member 22112 is in the second position, the second member22112 limits movement of the first member 22102 in the proximaldirection along the longitudinal axis L_(A) and relative to the adjacentspinous processes SP1 and SP2. The second member 22112 can limitmovement of the first member 22102, for example, by contacting and/orengaging the spinous processes SP1 and SP2 (e.g., either directly orthrough surrounding tissue).

As shown in FIG. 81, when the second member 22112 is in the firstposition, the second surface 22137 of the second member 22112 is incontact with and/or adjacent to at least a portion of the second surface22117 of the first member 22102. When the second member 22112 is in thesecond position, at least a portion 22131 of the second surface 22137(indicated by the shaded region in FIG. 84) is spaced apart from theportion of the second surface 22117 of the first member 22102. In thismanner, the portion 22131 of the second surface 22137 can limit movementof the first member 22102 by contacting and/or engaging the spinousprocesses SP1 and/or SP2 (e.g., either directly or through surroundingtissue). Although the second surface 22137 of the second member 22112 isshown in FIG. 81 as being in continuous contact with at least a portionof the second surface 22117 of the first member 22102, it is understoodthat portions of the second surface 22137 of the second member 22112 canbe spaced apart from the second surface 22117 of the first member 22102.For example, in some embodiments, portions of the second surface 22137of the second member 22112 can be spaced apart from the second surface22117 of the first member 22102 as a result of surface roughness,corrugation and/or waviness of the second surface 22137 of the secondmember 22112 and/or the second surface 22117 of the first member 22102.

Similarly stated, when the second member 22112 is in the first position,a cross-sectional area A₂ bounded by an outer surface of the secondmember 22112 (e.g., the area bounded by the second surface 22137) iswithin a cross-sectional area A₁ bounded by an outer surface of thefirst member 22102 (e.g., the area bounded by the second surface 22117)when the areas A₁ and A₂ are projected on a plane substantially normalto the longitudinal axis L_(A) (see FIG. 82). When the second member22112 is in the second position, a portion of the cross-sectional areaA₂ bounded by the outer surface of the second member 22112 (e.g., thearea bounded by the portion 22131 of the second surface 22137) isoutside of the cross-sectional area A₁ bounded by an outer surface ofthe first member 22102 when the areas A₁ and A₂ are projected on a planesubstantially normal to the longitudinal axis L_(A) (see FIG. 84).

Said another way, when the second member 22112 is in the first position,the first dimension X₂ of the second member 22112 is aligned with (e.g.,is substantially parallel to) the first dimension X₁ of the first member22102. Because the first dimension X₂ of the second member 22112 is nogreater than the first dimension X₁ of the first member 22102 and thesecond dimension Y₂ of the second member 22112 is no greater than thesecond dimension Y₁ of the first member 22102, when the second member22112 is in the first position, the footprint of the second member 22112(e.g., the shape of a portion of the second member 22112, such as forexample, the shape corresponding to the area A₂ bounded by the outersurface of the second member 22112) is within the footprint of the firstmember 22102 (e.g., the shape of a portion of the first member 22102,such as for example, the shape corresponding to the area A₁ bounded bythe outer surface of the first member (22102).

When the second member 22112 is in the second position, the seconddimension Y₂ of the second member 22112 is aligned with the firstdimension X₁ of the first member 22102 (i.e., the second member 22112 isrotated approximately 90 degrees relative to the first member 22102).Because the first dimension X₂ of the second member 22112 is greaterthan the second dimension Y₁ of the first member 22102, a portion of thefootprint of the second member 22112 is disposed outside of thefootprint of the first member 22102. In this manner, when the secondmember 22112 is in the first position, the implant 22100 can be insertedbetween the spinous processes SP1 and SP2 unimpeded by the second member22112 (i.e., the second member 22112 does not limit movement of thefirst member 22102 relative to the spinous processes SP1 and SP2).Conversely, when the second member 22112 is in the second position, aportion of the second member 22112 can contact and/or engage the firstspinous process SP1 and/or the second spinous process SP2 to limitlongitudinal movement of the first member 22102 relative to the spinousprocesses SP1 and SP2.

In use, the adjacent spinous processes SP1 and SP2 can be distractedprior to inserting the implant 22100 into the patient. An accesspassageway can then be defined to allow insertion of the implant 22100.The passageway can have any suitable shape (e.g., curved in twodimensions, curved in multiple planes or the like) and can be formed byany suitable method and by any suitable tool, as discussed herein. Afterthe access passageway is defined, the implant 22100 is insertedpercutaneously and advanced along the longitudinal axis L_(A) until itis positioned between the spinous processes SP1 and SP2. The implant22100 is inserted with the second member 22112 first and in the firstposition. Once the implant 22100 is in place, the second member 22112 ismoved to the second position to limit lateral movement of the firstmember 22102 in the proximal direction the longitudinal axis L_(A) andrelative to the spinous processes SP1 and SP2.

If or when it is desirable to change the position of the implant 22100and/or remove the implant 22100, the second member 22112 can be movedback to the first position, thereby allowing the first member 22102 tobe moved laterally. Once the first member 22102 is repositioned asdesired, the second member 22112 can be moved back to the secondposition, if desired.

Although the axis of rotation L_(R) is shown as being coincident withthe longitudinal axis L_(A), in other embodiments, the axis of rotationL_(R) can be offset from and parallel to the longitudinal axis L_(A). Inother embodiments, the axis of rotation L_(R) can be angularly offsetfrom the longitudinal axis L_(A) (i.e., the axis of rotation L_(R) andthe longitudinal axis L_(A) intersect). Similarly, although the secondmember 22112 is shown and described as being rotatably coupled to thefirst member 22102, in other embodiments, the second member 22112 canmovably coupled to the first member 22102 such that the second member22112 translates relative to the first member 22102 between the firstposition and the second position.

Although the first dimension X₂ of the second member 22112 is shown inFIG. 82 as being less than the first dimension X₁ of the first member22102, in some embodiments the first dimension X₂ of the second member22112 can be substantially equal to the first dimension X₁ of the firstmember 22102. Similarly, although the second dimension Y₂ of the secondmember 22112 is shown in FIG. 82 as being less than the second dimensionY₁ of the first member 22102, in some embodiments the second dimensionY₂ of the second member 22112 can be substantially equal to the seconddimension Y₁ of the first member 22102. In this manner, the firstsurface 22116 of the first member 22102 and the first surface 22136 ofthe second member 22112 can collectively form a continuous surface.

Although a portion 22131 of the second surface 22137 of the secondmember 22112 is shown and described as being in contact with at least aportion of the second surface 22117 of the first member 22102 when thesecond member 22112 is in the first position, in other embodiments theentire second surface 22137 of the second member 22112 can be spacedapart from the second surface 22117 of the first member 22102 when thesecond member 22112 is in the first position. For example, in someembodiments, the second surface of the second member can becomplementarily disposed adjacent at least a portion of the secondsurface of the first member when the second member is in the firstposition. The second surface of the second member can be disposed apartfrom (e.g., out of alignment with) the portion of the second surface ofthe first member when the second member is in the second position. Inthis manner the first member and the second member can be spaced apartto allow the second member to move relative to the first member withouttouching the first member.

Although a portion 22131 of the second surface 22137 of the secondmember 22112 is shown and described as being spaced apart from thesecond surface 22117 of the first member 22102 when the second member22112 is in the second position, in other embodiments the entire secondsurface 22137 of the second member 22112 can remain in contact with thesecond surface 22117 of the first member 22102 when the second member22112 is in the second position. For example, FIGS. 85-90 are schematicillustrations of an implant 22200 according to an embodiment of theinvention. FIGS. 85 and 88 are posterior views of the implant 22200 in afirst configuration and a second configuration, respectively, disposedbetween a first spinous process SP1 and a second spinous process SP2adjacent the first spinous process SP1. FIGS. 86 and 89 are side viewsof the implant 22200 in the first configuration and the secondconfiguration, respectively disposed between the spinous processes SP1and SP2. FIGS. 87 and 90 are cross-sectional views of the implant 22200taken along lines A-A in FIGS. 86 and 89, respectively.

The implant 22200 includes a first member 22202 and a second member22212 movably coupled to the first member 22202. The first member 22202has a proximal portion 22204, a distal portion 22206, a first surface22216, and a second surface 22217. The first surface 22216 of the firstmember 22202 is substantially parallel to a longitudinal axis L_(A) ofthe first member 22202. Said another way, the longitudinal axis L_(A)and a line defined to include a portion of the first surface 22216 ofthe first member 22202 are non-intersecting as they extend to infinity.Said yet another way, in embodiments in which the first surface 22216 ofthe first member 22202 includes at least a planar portion, every pointalong the longitudinal axis L_(A) is spaced apart from the nearestportion of a plane defined to include the planar portion of the firstsurface 22216 of the first member 22202 by a substantially equaldistance. The longitudinal axis L_(A) can, for example, pass lengthwise(e.g., from the proximal portion 22204 to the distal portion 22206)through the centroid of the first member 22202. As shown, when theimplant 22200 is disposed between the first spinous process SP1 and thesecond spinous process SP2, the longitudinal axis L_(A) can besubstantially parallel and/or coincident with a lateral axis defined bythe spinal column.

As shown, at least a portion of the first surface 22216 of the firstmember 22202 is disposed between the first spinous process SP1 and thesecond spinous process SP2. In this manner, the implant 22200 canmaintain a minimal spacing between the adjacent spinous processes SP1and SP2 during extension of the spinal column (not shown FIGS. 81-84)while allowing flexion of the spinal column.

The second surface 22217 is disposed at the distal portion 22206 of thefirst member 22202 and intersect the longitudinal axis L_(A) at an angleof approximately 90 degrees. Said another way, the second surface 22217of the first member 22202 is substantially normal to the first surface22216 of the first member 22202.

The second member 22212 has a first surface 22236, a second surface22237 and a saddle surface 22251. The first surface 22236 issubstantially parallel to the longitudinal axis L_(A) of the firstmember 22202. Said another way, the longitudinal axis L_(A) and a linedefined to include a portion of the first surface 22236 of the secondmember 22212 are non-intersecting as they extend to infinity. Said yetanother way, in embodiments in which the first surface 22236 of thesecond member 22212 includes at least a planar portion, every pointalong the longitudinal axis L_(A) is spaced apart from the nearestportion of a plane defined to include the planar portion of the firstsurface 22236 of the second member 22212 by a substantially equaldistance. The second surface 22237 intersects the longitudinal axisL_(A) at an angle of approximately 90 degrees. Said another way, thesecond surface 22237 of the second member 22212 is substantiallyparallel to the second surface 22217 of the first member 22202,substantially normal to the first surface 22236 of the second member22212, and substantially normal to the first surface 22216 of the firstmember 22202. The saddle surface 22251 is adjacent the second surface22237 and has a curved shape that can form a portion of a saddle 22252,as discussed in more detail herein.

The second member 22212 is coupled to the distal portion 22206 of thefirst member 22202 such that the second surface 22237 of the secondmember 22212 is in contact with a portion of the second surface 22217 ofthe first member 22202. The second member 22212 is rotatably coupled tothe first member 22202 about an axis of rotation L_(R) substantiallyparallel to and offset from the longitudinal axis L_(A). As indicated bythe arrows BB in FIGS. 88-90, the second member 22212 can rotaterelative to the first member 22202 between a first position (FIGS.85-87) and a second position (FIGS. 88-90).

As shown in FIGS. 85-87, when the second member 22212 is in the firstposition, a cross-sectional area A₂ bounded by an outer surface of thesecond member 22212 (i.e., the cross-sectional area of the second member22212 taken along line A-A in FIG. 86) is within a cross-sectional areaA₁ bounded by an outer surface of the first member 22202 (i.e., the areaof the second surface 22217) when projected on a plane substantiallynormal to the longitudinal axis L_(A) (see FIG. 87). As shown in FIGS.88-90, when the second member 22212 is in the second position, a portionof the cross-sectional area A₂ of the second member 22212 is outside ofthe cross-sectional area A₁ of the first member 22202 when the areas A₁and A₂ are projected on a plane substantially normal to the longitudinalaxis L_(A) (see FIG. 90). As shown in FIG. 86, the cross-sectional areaA₂ of the second member 22212 need not coincide with the second surface22237 of the second member 22212, but rather can be considered at anylongitudinal location along the second member 22212 (e.g., at the widestpoint of the second member 22212). Similarly, although thecross-sectional area A₁ of the first member 22202 is shown as being thearea of the second surface 22217, in other embodiments, thecross-sectional area A₁ of the first member 22202 can be considered atany longitudinal location along the first member 22202.

As shown in FIG. 88, when the second member 22212 is in the secondposition, the first surface 22216 of the first member 22202 and thesaddle surface 22251 of the second member 22212 collectively form aportion of a saddle 22252 configured to receive a portion of the spinousprocess SP1. In this manner, the saddle 22252 can receive and/or engagea portion of the spinous process SP1 and/or its surrounding tissue tolimit movement of the first member 22202 along the longitudinal axisL_(A) and relative to the spinous processes SP1 and SP2. In someembodiments, the saddle 22252 and/or the saddle surface 22251 can have acurved surface that substantially corresponds to a shape and/or a sizeof the spinous process SP1 (e.g., the spinous process SP1 and/or thesurrounding tissue). In some embodiments, the shape and/or size of thesaddle surface 22251 can be configured to more evenly distribute forcesbetween the saddle 22252 and the spinous process SP1. In someembodiments, the saddle surface 22251 and the first surface 22216 of thefirst member 22202 can form a substantially smooth and/or continuoussurface.

Returning to FIGS. 81-84, although the first surface 22116 of the firstmember 22102 and the first surface 22136 of the second member 22112 areshown and described as being substantially parallel to the longitudinalaxis L_(A), the first surface 22116 of the first member 22102 and/or thefirst surface 22136 of the second member 22112 can have any suitableshape, contour and/or orientation. For example, in some embodiments, thefirst surface 22116 of the first member 22102 can have a curved shape toform a portion of a saddle, as described above. In other embodiments, afirst surface of a first member can be tapered. For example, FIGS. 91-94are schematic illustrations of an implant 22300 according to anembodiment of the invention. FIGS. 91 and 93 are posterior views of theimplant 22300 in a first configuration and a second configuration,respectively, disposed between a first spinous process SP1 and a secondspinous process SP2. FIGS. 92 and 94 are side views of the implant 22300in the first configuration and the second configuration, respectively,disposed between the spinous processes SP1 and SP2.

The implant 22300 includes a first member 22302 and a second member22312 movably coupled to the first member 22302. The first member 22302has a proximal portion 22304, a distal portion 22306, a first surface22316, and a second surface 22317. The first surface 22316 of the firstmember 22302 is tapered in a direction substantially parallel to alongitudinal axis L_(A) of the first member 22302 such that a size Y₃ ofthe distal portion 22306 is less than a size Y₄ of the proximal portion22304. In this manner, when a portion of the first surface 22316 of thefirst member 22202 is disposed between the first spinous process SP1 andthe second spinous process SP2, the tapered of the first member 22302can contact and/or engage the spinous process SP1 (either directly orindirectly through its surrounding tissue) to limit movement of thefirst member 22302 along the longitudinal axis L_(A) and relative to theadjacent spinous processes SP1 and SP2.

The distal portion 22306 of the first member 22302 includes the secondsurface 22317, which intersects the longitudinal axis L_(A) at an acuteangle Θ. Said another way, the second surface 22317 of the first member22302 is angularly offset from the longitudinal axis L_(A) by an anglegreater than zero degrees and less than 90 degrees.

The second member 22312 has a first surface 22336 and a second surface22337. The first surface 22336 is substantially parallel to thelongitudinal axis L_(A) of the first member 22302. Said another way, thelongitudinal axis L_(A) and a line defined to include a portion of thefirst surface 22336 of the second member 22112 are non-intersecting asthey extend to infinity. Said yet another way, in embodiments in whichthe first surface 22336 of the second member 22312 includes at least aplanar portion, every point along the longitudinal axis L_(A) is spacedapart from the nearest portion of a plane defined to include the planarportion of the first surface 22136 of the second member 22112 by asubstantially equal distance. The second surface 22337 intersects thelongitudinal axis L_(A) at the acute angle Θ. Said another way, thesecond surface 22237 of the second member 22212 is substantiallyparallel to the second surface 22217 of the first member 22202.

As described above, the second member 22312 is rotatably coupled to thedistal portion 22306 of the first member 22302 about an axis of rotationL_(R) such that the second member 22312 can rotate relative to the firstmember 22302 between a first position (FIGS. 91 and 92) and a secondposition (FIGS. 93 and 94). When the second member 22312 is in the firstposition, the second surface 22337 of the second member 22312 is incontact with at least a portion of the second surface 22317 of the firstmember 22302. When the second member 22312 is in the second position, atleast a portion of the second surface 22337 is spaced apart from theportion of the second surface 22317 of the first member 22302. In thismanner, the portion of the second surface 22337 can limit movement ofthe first member 22302 by contacting and/or engaging the spinous processSP2 (either directly or indirectly through its surrounding tissue).

Although the first member 22302 is shown as being asymmetrically taperedalong the longitudinal axis L_(A) (i.e., tapered on the first surface22316 without being tapered on at least one other surface), in someembodiments, the first member 22302 can be symmetrically tapered alongthe longitudinal axis L_(A). In other embodiments, the first member22302 can be tapered along the longitudinal axis L_(A) in two dimensions(i.e., a height and a width).

FIGS. 95-99 show an implant 22400 according to an embodiment of theinvention. FIGS. 95 and 96 are perspective views of the implant 22400 ina first configuration and a second configuration, respectively. FIGS.97-99 are perspective views of portions of the implant 22400. Theimplant 22400 includes a support member 22402, a proximal retentionmember 22410 and a distal retention member 22412.

The support member 22402 has a proximal portion 22404, a distal portion22406 and a support surface 22416. The support surface 22416 isconfigured to be disposed between adjacent spinous processes (not shownin FIGS. 95-99) to maintain a minimal spacing between the spinousprocesses during extension of the spinal column. Accordingly, thesupport member 22402 can be constructed from any biocompatible materialhaving sufficient strength, such as, for example, stainless steel,plastic, polyetheretherketone (PEEK), carbon fiber, ultra-high molecularweight (UHMW) polyethylene, and the like.

The proximal portion 22404 of the support member 22402 includes aproximal end surface 22418 substantially normal to the support surface22416 of the support member 22402. Similarly, the distal portion 22406of the support member 22402 includes a distal end surface 22417substantially normal to the support surface 22416 of the support member22402. As shown in FIG. 97, the proximal end surface 22418 includes aprotrusion 22414 and defines a first opening 22409 that extends throughthe support member 22402 and receives a pivot rod 22470, as described inmore detail herein. The distal end surface 22417 defines a secondopening 22408 (shown in hidden lines) that receives a portion of alocking member 22454 and a biasing member 22458, as described in moredetail herein.

As shown in FIG. 99, the proximal retention member 22410 includes aretention surface 22447 that is substantially parallel to the proximalend surface 22418 of the support member 22402. The retention surface22447 of the proximal retention member 22410 defines a first opening22448 and a second opening 22449. The first opening 22448 receives theproximal end portion 22471 of the pivot rod 22470. The second opening22449 has an arcuate shape and receives a portion of the protrusion22414 of the support member 22402. In this manner, as described in moredetail herein, when the proximal retention member 22410 rotates relativeto the support member 22402, the protrusion 22414 moves within secondopening 22449 to limit end positions of the rotation of the proximalretention member 22410 relative to the support member 22402.

Similarly, as shown in FIG. 98, the distal retention member 22412includes an outer surface 22436 and a retention surface 22437. The outersurface 22436 of the distal retention member 22412 has a curved shape tofacilitate insertion of the implant 22400 into the body. For example, insome embodiments, the outer surface 22436 of the distal retention member22412 can be configured to displace a bodily tissue, dilate a bodilytissue and/or distract a space between adjacent spinous processes. Theouter surface 22436 of the distal retention member 22412 also definestwo recesses 22439, one of which receives an end portion 22457 of thelocking member 22454 when the implant 22400 is in the secondconfiguration (see FIG. 96).

The retention surface 22437 of the distal retention member 22412 issubstantially parallel to the distal end surface 22417 of the supportmember 22402. The retention surface 22437 of the distal retention member22412 defines a recess 22438 that receives the end portion 22457 of thelocking member 22454.

The proximal retention member 22410 and the distal retention member22412 are rotatably coupled to the support member 22402 by the pivot rod22470. As shown in FIG. 98, a distal end portion 22472 of the pivot rod22470 is affixed to the retention surface 22437 of the distal retentionmember 22412. In some embodiments, for example, the distal end portion22472 of the pivot rod 22470 can be affixed to the retention surface22437 by disposing a portion of the distal end portion 22472 of thepivot rod 22470 within an opening (not shown in FIG. 98) defined by theretention surface 22437. In such embodiments, the opening and the distalend portion 22472 of the pivot rod 22470 can be configured to produce aninterference fit. Similarly, in such embodiments, the distal end portion22472 of the pivot rod 22470 can be welded to the retention surface22437.

The pivot rod 22470 extends through the first opening 22409 of thesupport member 22402 such that the proximal end portion 22471 of thepivot rod 22470 is received within the first opening 22448 of theproximal retention member 22410 and is fixedly coupled to the proximalretention member 22410. In this manner, the proximal retention member22410 and the distal retention member 22412 are coupled together and cancollectively rotate relative to the support member 22402 about an axisof rotation L_(R) (which is coincides with the center line of the pivotrod 22470), as indicated by the arrows CC in FIG. 96.

The proximal retention member 22410 and the distal retention member22412 can collectively rotate relative to the support member 22402between a first position (i.e., the first configuration of the implant22400, as shown in FIG. 95) and a second position (i.e., the secondconfiguration of the implant 22400, as shown in FIG. 96). When theproximal retention member 22410 and the distal retention member 22412are in the first position, the retention surface 22447 of the proximalretention member 22410 is in contact with and/or adjacent to theproximal end surface 22418 of the support member 22402 and the retentionsurface 22437 of the distal retention member 22412 is in contact withand/or adjacent to the distal end surface 22417 of the support member22402. In this manner, the implant 22400 can be inserted betweenadjacent spinous processes unimpeded by the proximal retention member22410 and/or the distal retention member 22412 (i.e., the proximalretention member 22410 and/or the distal retention member 22412 do notlimit movement of the support member 22402 relative to the spinousprocesses). As described above, it is understood that portions of theretention surface 22447 and the retention surface 22437 can be spacedapart from the proximal end surface 22418 and the distal end surface22417, respectively. For example, in some embodiments, portions of theretention surface 22447 and/or the retention surface 22437 of the secondmember 22412 can be spaced apart from the proximal end surface 22418and/or the distal end surface 22417, respectively, as a result ofsurface roughness, corrugation and/or waviness of the mating surfaces.

Similarly stated, when the proximal retention member 22410 and thedistal retention member 22412 are in the first position, the area A₂ ofthe proximal retention surface 22447 is within the area A₁ of theproximal end surface 22418 of the support member 22402 when the areas A₁and A₂ are projected on a plane substantially parallel to the proximalend surface 22418 of the support member 22402. Similarly, the area A₄ ofthe distal retention surface 22437 is within the area A₃ of the distalend surface 22417 of the support member 22402 when the areas A₃ and A₄are projected on a plane substantially parallel to the distal endsurface 22417 of the support member 22402.

Moreover, when the implant 22400 is in the first configuration, thebiasing member 22458 exerts a force against the locking member 22454such that the end portion 22457 of the locking member 22454 is disposedoutside of the support member 22402 and is received within the recess22438 of the retention surface 22437 of the distal retention member22412. Accordingly, when the implant 22400 is in the firstconfiguration, the locking member 22454 temporarily maintains the distalretention member 22412 and the proximal retention member 22410 in thefirst position. The recess 22438 of the retention surface 22437 has acurved shape that substantially corresponds to a shape of the endportion 22457 of the locking member 22454. When a rotational force isapplied to the proximal retention member 22410 and/or the distalretention member 22412, as shown by the arrow CC in FIG. 96, a resultingforce is produced that moves the end portion 22457 of the locking member22454 into the opening 22408 of the support member 22402. In thismanner, the implant 22400 can be moved into the second configurationwhen disposed between adjacent spinous processes. Although the lockingmember 22454 is shown as being a cylindrical pin, in other embodiments,any suitable detent can used to maintain the implant 22400 in the firstconfiguration.

When the proximal retention member 22410 and the distal retention member22412 are in the second position, at least a portion of the proximalretention surface 22447 and at least a portion of the distal retentionsurface 22437 are spaced apart from the proximal end surface 22418 ofthe support member 22402 and the distal end surface 22417 of the supportmember 22402, respectively. In this manner, when implant 22400 is in thesecond configuration, the portion of the proximal retention surface22447 and/or the portion of the distal retention surface 22437 cancontact and/or engage the spinous processes to limit lateral movement ofthe support member 22402 relative to the spinous processes.

When the proximal retention member 22410 and the distal retention member22412 are in the second position, a portion of the area A₂ of theproximal retention surface 22447 is outside of the area A₁ of theproximal end surface 22418 of the support member 22402 when projected ona plane substantially parallel to the proximal end surface 22418 of thesupport member 22402. Similarly, a portion of the area A₄ of the distalretention surface 22437 is outside of the area A₃ of the distal endsurface 22417 of the support member 22402 when projected on a planesubstantially parallel to the distal end surface 22417 of the supportmember 22402.

Moreover, when the implant 22400 is in the second configuration, thebiasing member 22458 exerts a force against the locking member 22454such that the end portion 22457 of the locking member 22454 is received,at least partially, within one of the recesses 22439 of the outersurface 22436 of the distal retention member 22412. Accordingly, whenthe implant 22400 is in the second configuration, the locking member22454 maintains the distal retention member 22412 and the proximalretention member 22410 in the second position. The recesses 22439 of theouter surface 22437 are configured to receive, at least partially, theend portion 22457 of the locking member 22454 such that the distalretention member 22412 and the proximal retention member 22410 arereleasably locked in the second position. In this manner, in someembodiments, a deployment tool, of the types shown and described herein,is used to move the locking member 22454 into the opening 22408 of thesupport member 22402 so that the implant 22400 can be moved from thesecond configuration to the first configuration. The locking member22454 is retained within the second opening 24408 by the retainer 22458.The retainer 22458 can be coupled within the opening 24408, for example,by an interference fit, a weld, a swaged fit or the like.

Moreover, when the implant 22400 is in the second configuration, theprotrusion 22414 of the proximal end surface 22418 can be in contactwith the retention surface 22447 of the proximal retention member 22410that defines an end portion of the arcuate opening 22449. In thismanner, the proximal retention member 22410 is prevented from beingrotated more than approximately 90 degrees from the first position. Saidanother way, the protrusion 22414 and the surfaces defining the arcuateopening 22449 limit the rotation of the proximal retention member 22410relative to the support member 22402.

Although the locking member 22454 is shown as being disposed within thesupport member 22402 such that an end portion 22457 of the lockingmember 22454 is received within the recesses 22438 and/or 22439, inother embodiments, a locking member can be disposed within a proximalretention member and/or a distal retention member such that an endportion of the locking member is received within a recess in theproximal end surface of the support member and/or the distal end surfaceof the support member to temporarily maintain the implant in a firstand/or a second configuration. In other embodiments, a locking membercan be coupled to an outer surface of the support member such that aportion of the locking member is received within recesses defined by anouter surface of a proximal retention member and/or a distal retentionmember. In yet other embodiments, an implant can include a first lockingmember or detent to temporarily maintain the implant in a firstconfiguration and a second locking member or detent to temporarilymaintain the implant in a second configuration.

Although the proximal retention member 22410 and the distal retentionmember 22412 are shown and described as being disposed adjacent theproximal end surface 22417 and the distal end surface 22418 of thesupport member 22402, in other embodiments, an implant can include aretention member disposed at a location other than at a proximal endsurface or a distal end surface. For example, in some embodiments, animplant can include a retention member disposed in a central portion ofa support member. In some embodiments, a retention member can be movablycoupled to a support member such that the retention member is disposedwithin the support member when the retention member is in a firstposition and at least a portion of the retention member is disposedoutside of the support member when the retention member is in a secondposition.

FIGS. 100-105 show an implant 22500 according to an embodiment of theinvention. FIGS. 100-102 show a perspective view, a front view and abottom view, respectively, of the implant 22500 in a firstconfiguration. FIGS. 103-105 show a perspective view, a front view and abottom view, respectively, of the implant 22500 in a secondconfiguration. The implant 22500 includes a support member 22502, aproximal retention member 22510 and a distal retention member 22512.

The support member 22502 has a proximal portion 22504, a distal portion22506 and a support surface 22516. The support surface 22516 isconfigured to be disposed between adjacent spinous processes (not shownin FIGS. 100-105) to maintain a minimal spacing between the spinousprocesses during extension of the spinal column. The support surface22516 defines a recess 22549 having two shoulder surfaces 22560. Asdescribed in more detail herein, the shoulder surfaces 22560 areconfigured to engage a protrusion 22514 of the proximal retention member22510 to limit the end positions of the rotation of the proximalretention member 22510 relative to the support member 22502.

The proximal portion 22504 of the support member 22502 includes aproximal end surface 22518 substantially normal to the support surface22516 of the support member 22502. Similarly, the distal portion 22506of the support member 22502 includes a distal end surface 22517substantially normal to the support surface 22516 of the support member22502. As shown in FIGS. 107 and 110, the proximal end surface 22518defines a first opening 22509 that extends through the support member22502 and receives a pivot rod 22570. As shown in FIGS. 107 and 110, thedistal end surface 22517 defines a second opening 22508 that receives aportion of a locking member 22554 and a biasing member 22558, asdescribed in more detail herein.

The proximal retention member 22510 includes an outer surface 22546, aproximal end surface 22561 and retention surface 22547. The outersurface 22546 has a curved surface that substantially corresponds to ashape and/or a size of the support surface 22516 of the support member22502. In this manner, the outer surface 22546 of the proximal retentionmember 22510 and the support surface 22516 of the support member 22502can form a substantially smooth and/or continuous surface when theimplant 22500 is in the first configuration.

As shown in FIGS. 107-109, the proximal end surface 22561 of theproximal retention member 22510 is configured to be received within areceiving area 22642 of a deployment tool 22600. The proximal endsurface 22561 defines a threaded opening 22580 configured engage athreaded portion 22672 of a rod 22670 of the deployment tool 22600.

The retention surface 22547 of the proximal retention member 22510 issubstantially parallel to the proximal end surface 22518 of the supportmember 22502. The retention surface 22547 of the proximal retentionmember 22510 defines an opening 22548 and a protrusion 22514. As shownin FIGS. 107 and 110, the opening 22548 receives the proximal endportion 22471 of the pivot rod 22570. The outer surface 22546 alsodefines an opening 25584. The opening 25584 can be used, for example,during the assembly of the implant 22500 to ensure that the proximal endportion 22471 of the pivot rod 22570 is properly positioned and/oraffixed within the opening 22509. In some embodiments, the opening 22584can be welded closed.

The protrusion 22514 of the proximal retention member 22510 is receivedwithin the recess 22549 defined by the support surface 22516. When theproximal retention member 22510 rotates relative to the support portion22502, the protrusion 22514 contacts the shoulder surfaces 22560 (seee.g., FIGS. 104 and 105) to limit the end positions of the rotation ofthe proximal retention member 22510 relative to the support member22502.

Similarly, the distal retention member 22512 includes an outer surface22536 and a retention surface 22537. The outer surface 22536 of thedistal retention member 22512 has a curved shape (e.g., a tapered endportion) and includes a tip 22535 to facilitate insertion of the implant22500 into the body. In some embodiments, for example, the outer surface22436 and/or the tip 22535 can displace a bodily tissue when the implant22500 is inserted into the body. In some embodiments, the outer surface22436 and/or the tip 22535 can dilate a bodily tissue, such as thesupraspinous ligament, when the implant 22500 is inserted into the body.In some embodiments, the outer surface 22436 and/or the tip 22535 candistract a space between adjacent spinous processes when the implant22500 is inserted into the body.

The shape of the outer surface 22536 of the distal retention member22512 is asymmetrical such that when the implant 22500 is in the secondconfiguration, a portion of the support surface 22516 of the supportmember 22502 and a portion of the outer surface 22536 of the distalretention member 22512 form a substantially continuous and/or linearsurface (see e.g., FIG. 105). In this manner, when the implant 22500 isin the second configuration, the substantially continuous and/or linearsurface formed by the support surface 22516 of the support member 22502and the outer surface 22536 of the distal retention member 22512 canlimit rotational movement of the implant 22500 about an axis normal tothe axis L_(R) (e.g., in a direction as indicated by the arrow JJ inFIG. 105). Said another way, the substantially continuous and/or linearsurface formed by the support surface 22516 of the support member 22502and the outer surface 22536 of the distal retention member 22512 canprevent the implant 22500 from rotating out of its position between theadjacent spinous processes.

The outer surface 22536 of the distal retention member 22512 defines tworecesses 22539, one of which receives an end portion 22557 of thelocking member 22454 when the implant 22500 is in the secondconfiguration (see FIG. 103). The outer surface 22536 of the distalretention member 22512 also defines a threaded opening 22582 configuredengage the threaded portion 22672 of a rod 22670 of the deployment tool22600.

The retention surface 22537 of the distal retention member 22512 issubstantially parallel to the distal end surface 22517 of the supportmember 22502. The retention surface 22537 of the distal retention member22512 defines a recess 22538 that receives the end portion 22557 of thelocking member 22554.

The proximal retention member 22510 and the distal retention member22512 are rotatably coupled to the support member 22502 by the pivot rod22570, as described above. As shown in FIG. 107, the pivot rod 22570extends through the first opening 22509 of the support member 22502 suchthat the proximal end portion 22571 of the pivot rod 22570 is receivedwithin the first opening 22548 of the proximal retention member 25510and is fixedly coupled to the proximal retention member 22510. In thismanner, the proximal retention member 22510 and the distal retentionmember 22512 are coupled together and can collectively rotate relativeto the support member 22502 about an axis of rotation L_(R) (which iscoincides with the center line of the pivot rod 22570), as indicated bythe arrows KK in FIG. 105.

The proximal retention member 22510 and the distal retention member22512 can collectively rotate relative to the support member 22502between a first position (i.e., the first configuration of the implant22500, as shown in FIGS. 100-102) and a second position (i.e., thesecond configuration of the implant 22500, as shown in FIG. 103-105).When the implant 22500 is in the first configuration, the retentionsurface 22547 of the proximal retention member 22510 is in contact withand/or adjacent to the proximal end surface 22518 of the support member22502 and the retention surface 22537 of the distal retention member22512 is in contact with and/or adjacent to the distal end surface 22517of the support member 22502. In this manner, the implant 22500 can beinserted between adjacent spinous processes unimpeded by the proximalretention member 22510 and/or the distal retention member 22512 (i.e.,the proximal retention member 22510 and/or the distal retention member22512 do not limit movement of the support member 22502 relative to thespinous processes). As described above, it is understood that portionsof the retention surface 22547 and the retention surface 22537 can bespaced apart from the proximal end surface 22518 and the distal endsurface 22517, respectively. For example, in some embodiments, portionsof the retention surface 22547 and/or the retention surface 22537 of thesecond member 22512 can be spaced apart from the proximal end surface22518 and/or the distal end surface 22517, respectively, as a result ofsurface roughness, corrugation and/or waviness of the mating surfaces.

Similarly stated, when the implant 22500 is in the first configuration,the area A₂ of the proximal retention surface 22547 is within the areaA₁ of the proximal end surface 22518 of the support member 22502 whenthe areas A₁ and A₂ are projected on a plane substantially parallel tothe proximal end surface 22518 of the support member 22502. Similarly,when the implant 22500 is in the first configuration, the area A₄ of thedistal retention surface 22537 is within the area A₃ of the distal endsurface 22517 of the support member 22502 when the areas A₃ and A₄ areprojected on a plane substantially parallel to the distal end surface22517 of the support member 22502.

Moreover, when the implant 22500 is in the first configuration, thebiasing member 22558 exerts a force against the locking member 22554such that the end portion 22557 of the locking member 22554 is disposedoutside of the support member 22502 and is received within the recess22538 of the retention surface 22537 of the distal retention member22512. Accordingly, when the implant 22500 is in the firstconfiguration, the locking member 22554 temporarily maintains the distalretention member 22512 and the proximal retention member 22510 in thefirst position, as described above.

When the implant 22500 is in the second configuration, at least aportion of the proximal retention surface 22547 and at least a portionof the distal retention surface 22537 are spaced apart from the proximalend surface 22518 of the support member 22502 and the distal end surface22517 of the support member 22502, respectively. In this manner, whenimplant 22500 is in the second configuration, the portion of theproximal retention surface 22547 and/or the portion of the distalretention surface 22537 can contact and/or engage the spinous processes(or the associated surrounding tissue) to limit lateral movement of thesupport member 22502 relative to the spinous processes.

When the proximal retention member 22510 and the distal retention member22512 are in the second position, a portion of the area A₂ of theproximal retention surface 22547 is outside of the area A₁ of theproximal end surface 22518 of the support member 22502 when projected ona plane substantially parallel to the proximal end surface 22518 of thesupport member 22502. Similarly, a portion of the area A₄ of the distalretention surface 22537 is outside of the area A₃ of the distal endsurface 22517 of the support member 22502 when projected on a planesubstantially parallel to the distal end surface 22517 of the supportmember 22502.

Moreover, when the implant 22500 is in the second configuration, thebiasing member 22558 exerts a force against the locking member 22554such that the end portion 22557 of the locking member 22554 is received,at least partially, within one of the recesses 22539 of the outersurface 22536 of the distal retention member 22512. Accordingly, whenthe implant 22500 is in the second configuration, the locking member22554 maintains the distal retention member 22512 and the proximalretention member 22510 in the second position, as described above.

Moreover, when the implant 22500 is in the second configuration, theprotrusion 22514 of the proximal retention member 22510 can be incontact with one of the shoulder surfaces 22560 of the support member22502. In this manner, the proximal retention member 22510 is preventedfrom being rotated more than approximately 90 degrees from the firstposition. Said another way, the protrusion 22514 and the shouldersurfaces 22560 limit the rotation of the proximal retention member 22510relative to the support member 22502.

The implant 22500 can be inserted into and/or removed from the body by adeployment tool 22600, as shown in FIGS. 106-112. The deployment tool22600 includes a shaft 22620 and a rod 22670 movably disposed within theshaft 22620. The distal end of the shaft 22620 includes an implantsupport portion 26630. The implant support portion 26630 has a side wall22640 having an inner surface 22641, a first end face 22644 and a secondend face 22645. The inner surface 22641, the first end face 22644 andthe second end face 22645 collectively define a receiving area 22642. Asshown, the inner surface 22641 of the side wall 22640 is configured tocomplementarily receive the proximal retention member 22510 and thedistal retention member 22512 of the implant 22500. Moreover, the firstend face 22644 is set back proximally from the second end face 22645 toaccommodate the curved outer surface 22536 of the distal retentionmember 22512. In this manner, as described in more detail herein, theproximal retention member 22510 and/or the distal retention member 22512can be received within the receiving area 22642 of the deployment tool22600.

The rod 22670 includes a threaded portion 22672 that is positionedwithin the receiving area 22642. The rod 22670 is rotatable within theshaft 22620 such that the threaded portion 22672 of the rod 22670 can bethreadedly engaged with the threaded opening 22580 of the proximalretention member 22510 (see e.g., FIG. 107) and/or the threaded opening22582 of the distal retention member 22512 (see e.g., FIG. 110). In thismanner, the implant 22500 can be removably secured within the receivingarea 22642 of the deployment tool 22600. The rod 22670 can be rotatedwithin the shaft 22620 by any suitable mechanism, such as a knobassembly (not shown in FIGS. 106-112) of the type shown and describedabove with reference to FIGS. 11-16.

In use, with the implant 22500 in the first configuration, the proximalretention member 22510 of the implant 22500 can be secured within thereceiving area 22642 of the deployment tool 22600, as described above.As shown in FIG. 107, the proximal end surface 22561 of the proximalretention member 22510 can be in contact with the second end face 22645of the deployment tool 22600.

The implant 22500 can then be inserted percutaneously until at least aportion of the support surface 22516 of the support member 22502 isbetween adjacent spinous processes (not shown in FIGS. 106-112). In someembodiments, the implant 22500 can be deployed via a lateral accesspath. The path can have any suitable curvature and/or size, such asthose described herein.

When the implant 22500 is positioned between the adjacent spinousprocesses, the shaft 22620 is rotated about its center line CL, asindicated by the arrow LL in FIG. 109. When the shaft 22620 is rotated,the position of the support member 22502 is maintained by the adjacentspinous processes. In this manner, the proximal retention member 22510and the distal retention member 22512 are rotated relative supportmember 22502, thereby moving the implant 22500 from the firstconfiguration (FIG. 108) to the second configuration (FIG. 109). Thedeployment tool 22600 is decoupled from the implant 22500 by rotatingthe rod 22670 within the shaft 22620 until the threaded portion 22672 ofthe rod 22670 is no longer engaged with the threaded opening 22580 ofthe proximal retention member 22510.

The implant 22500 can be removed from and/or repositioned within thebody by positioning the deployment tool 22600 such that the distalretention member 22512 of the implant 22500 is within the receiving area22642, as shown in FIGS. 110-112. As shown in FIG. 111, when the distalretention member 22512 is within the receiving area 22642, the distalend surface 22635 of the implant support portion 26630 engages theportion 22557 of the locking member 22554 and moves the locking member22554 into the opening 22508. In this manner, the implant 22500 is“unlocked” and can be moved from the second configuration (FIG. 111)back to the first configuration (FIG. 112). As described above, theimplant 22500 can be moved to the first configuration by rotating theshaft 22620 about its center line CL, as indicated by the arrow MM inFIG. 112.

Although the rod 22670 is shown as being rotatable within the shaft22620, in other embodiments, the rod 22670 can both rotate and translatewithin the shaft 22620. For example, in some embodiments, a deploymenttool can have a knob assembly similar to the knob assembly shown anddescribed above with reference to FIGS. 11-16.

Although the implant 22500 is shown and described without reference toany specific dimensions, the implant 22500 can have any suitable size tobe disposed between any set of adjacent spinous processes within apatients body (ranging, for example, from the L4/L5 spinous processes tothe C1/C2 spinous processes). Referring to the dimensions shown in FIGS.101 and 102, in some embodiments, for example, the length L₁ of thesupport member 22502 can be between 8 mm and 16 mm. In some embodiments,the length L₁ of the support member 22502 can be approximately 12 mm.Similarly, in some embodiments, the length L₂ of the proximal retentionmember 22510 can be between 6 mm and 12 mm. In some embodiments, thelength L₂ of the proximal retention member 22510 can be approximately 9mm. Similarly, in some embodiments, the length L₃ of the distalretention member 22512 can be between 8 mm and 16 mm. In someembodiments, the length L₃ of the distal retention member 22512 can beapproximately 11 mm.

In some embodiments, the height H of the implant 22500 can be between 9mm and 22 mm. Similarly, in some embodiments, the width W of the implant22500 can be between 6 mm and 16 mm. In some embodiments, for example,the height H of the implant 22500 can be approximately 12 mm and thewidth W of the implant 22500 can be approximately 8 mm. As shown in FIG.105, the difference between the height H and the width W is the distanceD that the outermost edge of the proximal retention member 22510 and/orthe distal retention member 22512 are spaced apart from the supportsurface 22516 of the support member 22502 when the implant is in thesecond configuration. Said another way, the aspect ratio of the implant22500 (H divided by W) is associated with the distance D. In someembodiments, the aspect ratio of the implant 22500 is betweenapproximately 1.2 and 1.6.

FIG. 113 shows a method 23100 according to an embodiment of theinvention. The method includes disposing at least a portion of animplant between adjacent spinous processes, 23104. The implant includesa support member having a longitudinal axis, and a retention membermovably coupled to the support member. The implant can be any suitableimplant of the types shown and described above, such as for example, theimplant 22100.

In some embodiments, the disposing can include inserting the implantpercutaneously via a lateral access path. In some embodiments, thedisposing can include inserting the implant using a curved tool and/or aguide member, as described herein. In some embodiments, the method caninclude optionally distracting the adjacent spinous processes before thedisposing, 23102.

The retention member of the implant is then rotated from a firstposition to a second position such that the retention member retains aportion of the implant between the adjacent spinous processes, 23106. Insome embodiments, the retention member can be rotated about an axissubstantially parallel to the longitudinal axis of the support member.In some embodiments, for example, the support member has an end portionhaving a cross-sectional area normal to the longitudinal axis of thesupport member. The retention member also has a cross-sectional areanormal to the longitudinal axis of the support member. Thecross-sectional area of the retention member being within thecross-sectional area of the distal end of the support member projectedon a plane substantially normal to the longitudinal axis and when theretention member is in the first position. In such embodiments, therotating can include rotating the retention member such that a portionof the cross-sectional area of the retention member is outside of thecross-sectional area of the distal end of the support member whenprojected on the plane substantially normal to the longitudinal axis.

In some embodiments, the method can include optionally locking theretention member in the second position, 23108. The locking can include,for example, moving a locking member such that a portion of the lockingmember is received within a recess defined by the support member and/orthe retention member, as described above.

FIGS. 114-117 are schematic illustrations of an implant 24100 accordingto an embodiment of the invention. FIGS. 114 and 116 are posterior viewsof the implant 24100 in a first configuration and a secondconfiguration, respectively, disposed between a first spinous processSP1 and a second spinous process SP2 adjacent the first spinous processSP1. FIGS. 115 and 117 are lateral views of the implant 24100 in thefirst configuration and the second configuration, respectively, disposedbetween the first spinous process SP1 and the second spinous processSP2. The implant 24100 includes a support member 24102 and a retentionmember 24112 rotatably coupled to the support member 24102.

The support member 24102 has a proximal portion 24104, a distal portion24106 and an outer surface 24116. The outer surface 24116 of the supportmember 24102 is substantially parallel to a longitudinal axis L_(A) ofthe support member 24102. Said another way, the longitudinal axis L_(A)and a line defined to include a portion of the outer surface 24116 ofthe support member 24102 are non-intersecting as they extend toinfinity. Said yet another way, in embodiments in which the firstsurface 24116 of the support member 24102 includes at least a planarportion, every point along the longitudinal axis L_(A) is spaced apartfrom the nearest portion of a plane defined to include the planarportion of the first surface 24116 of the first member 22402 by asubstantially equal distance. The longitudinal axis L_(A) can, forexample, pass lengthwise (e.g., from the proximal portion 24104 to thedistal portion 24106) through the centroid of the support member 24102(e.g., the longitudinal axis L_(A) can be a centroidal axis of thesupport member 24102). As shown, when the implant 24100 is disposedbetween the first spinous process SP1 and the second spinous processSP2, the longitudinal axis L_(A) can be substantially parallel and/orcoincident with a lateral axis defined by the spinal column.

As shown, at least a portion of the outer surface 24116 of the supportmember 24102 is disposed between the first spinous process SP1 and thesecond spinous process SP2. In this manner, the implant 24100 canmaintain a minimal spacing between the adjacent spinous processes SP Iand SP2 during extension of the spinal column (not shown FIGS. 114-117)while allowing flexion of the spinal column. Moreover, in someembodiments, the implant 24100 can distract the adjacent spinousprocesses SP1 and SP2.

The retention member 24112 has a first end portion 24130, a second endportion 24132 and a central portion 24133 disposed between the first endportion 24130 and the second end portion 24132. The retention member24112 is rotatably coupled to the support member 24102 such that theretention member 24112 can rotate relative to the support member 24102about an axis of rotation L_(R) substantially normal to the longitudinalaxis L_(A). As indicated by the arrows FF in FIGS. 116 and 117, theretention member 24112 can rotate relative to the support member 24102between a first position (FIGS. 114 and 115) and a second position(FIGS. 116 and 117). When the retention member 24112 is in the firstposition, the implant 24100 can be inserted such that at least a portionof the first surface 24116 of the support member 24102 is disposedbetween the first spinous process SP1 and the second spinous processSP2. When the retention member 24112 is in the second position, theretention member 24112 limits lateral movement of the support member24102 along the longitudinal axis L_(A) and relative to the adjacentspinous processes SP1 and SP2. The retention member 24112 can limitlateral movement of the support member 24102, for example, by contactingthe spinous processes SP I and SP2 (e.g., either directly or throughsurrounding tissue).

As shown in FIGS. 114 and 115, when the retention member 24112 is in thefirst position, the outermost portion of the first end portion 24130 isspaced apart from the outer surface 24116 of the support member 24102 bya distance Y₁ along an axis substantially normal to the longitudinalaxis L_(A) and substantially normal to the axis of rotation L_(R). Thedistance Y₁ is such that the distance between the first end portion24130 and the longitudinal axis L_(A) is less than the distance betweenthe outer surface 24116 of the support member 24102 and the longitudinalaxis L_(A) (i.e., the first end portion 24130 of the retention member24112 is “below” the outer surface 24116 of the support member 24102relative to the longitudinal axis L_(A)). Similarly, when the retentionmember 24112 is in the first position, the outermost portion of thesecond end portion 24132 is spaced apart from the outer surface 24116 ofthe support member 24102 by a distance Y₂ along the axis substantiallynormal to the longitudinal axis L_(A) and substantially normal to theaxis of rotation L_(R). The distance Y₂, which, in some embodiments, canbe equal to the distance Y₁, is such that the distance between thesecond end portion 24132 and the longitudinal axis L_(A) is less thanthe distance between the outer surface 24116 of the support member 24102and the longitudinal axis L_(A) (i.e., the second end portion 24132 ofthe retention member 24112 is “below” the outer surface 24116 of thesupport member 24102 relative to the longitudinal axis L_(A)). In thismanner, when the retention member 24112 is in the first position, theimplant 24100 can be inserted between the spinous processes SP1 and SP2unimpeded by first end portion 24130 of the retention member 24112and/or the second end portion 24132 of the retention member 24112 (i.e.,the retention member 24112 does not limit movement of the support member24102 relative to the spinous processes SP1 and SP2).

As shown in FIGS. 116 and 117, when the retention member 24112 is in thesecond position, the outermost portion of the first end portion 24130 isspaced apart from the outer surface 24116 of the support member 24102 bya distance Y′₁ along the axis substantially normal to the longitudinalaxis L_(A) and substantially normal to the axis of rotation L_(R). Thedistance Y′₁ is such that the distance between the first end portion24130 and the longitudinal axis L_(A) is greater than the distancebetween the outer surface 24116 of the support member 24102 and thelongitudinal axis L_(A) (i.e., the first end portion 24130 of theretention member 24112 is “above” the outer surface 24116 of the supportmember 24102 relative to the longitudinal axis L_(A)). Similarly, whenthe retention member 24112 is in the second position, the outermostportion of the second end portion 24132 is spaced apart from the outersurface 24116 of the support member 24102 by a distance Y′₂ along theaxis substantially normal to the longitudinal axis L_(A) andsubstantially normal to the axis of rotation L_(R). The distance Y′₂,which in some embodiments can be equal to the distance Y′₁, is such thatthe distance between the second end portion 24132 and the longitudinalaxis L_(A) is greater than the distance between the outer surface 24116of the support member 24102 and the longitudinal axis L_(A) (i.e., thesecond end portion 24132 of the retention member 24112 is “above” theouter surface 24116 of the support member 24102 relative to thelongitudinal axis L_(A)). In this manner, when the retention member24112 is in the second position, the first end portion 24130 can contactthe first spinous process SP1 and/or the second end portion 24132 cancontact the second spinous process SP2 to limit movement of the supportmember 24102 relative to the spinous processes SP I and SP2.

In use, the adjacent spinous processes SP1 and SP2 can be distractedprior to inserting the implant 24100 into the patient. An accesspassageway can be then defined to allow insertion of the implant 24100.The passageway can have any suitable shape and can be formed by anysuitable method, as discussed herein. After the access passageway isdefined, the implant 24100 can be inserted percutaneously and advancedalong the longitudinal axis L_(A) until it is positioned between thespinous processes SP1 and SP2. The implant 24100 is inserted distalportion 24106 first and with the retention member 24112 in the firstposition. Once the implant 24100 is in place, the retention member 24112is moved to the second position to limit lateral movement of the supportmember 24102 with respect to the spinous processes SP1 and SP2.

If or when it is desirable to change the position of the implant 24100and/or remove the implant 24100, the retention member 24112 can be movedback to the first position, thereby allowing the support member 24102 tobe moved laterally. Once the support member 24102 is repositioned asdesired, the retention member 24112 can be moved back to the secondposition, if desired.

Although the first end portion 24130 and the second end portion 24132are shown and described as being “below” the outer surface 24116 of thesupport member 24102 relative to the longitudinal axis L_(A), in otherembodiments, the first end portion 24130 and/or the second end portion24132 can be flush with the outer surface 24116 of the support member24102 (i.e., the distance Y₁ and/or the distance Y₂ can be zero). Inother embodiments, the first end portion 24130 and/or the second endportion 24132 can be above the outer surface 24116 of the support member24102 by a distance that does not interfere with the insertion of theimplant 24100.

Although the retention member 24112 is shown as being coupled to theouter surface 24116 of the support member 24102, in some embodiments, atleast a portion of a retention member can be disposed within a supportmember. For example, FIGS. 118-123 show an implant 24200 according to anembodiment of the invention. FIGS. 118 and 121 are posterior views ofthe implant 24200 in a first configuration and a second configuration,respectively, disposed between a first spinous process SP1 and a secondspinous process SP2 adjacent the first spinous process SP1. FIGS. 119and 122 are posterior cross-sectional views of the implant 24200 in thefirst configuration and the second configuration, respectively, disposedbetween the spinous processes SP1 and SP2. FIGS. 120 and 123 arecross-sectional views of the implant 24200 taken along lines A-A inFIGS. 118 and 121, respectively.

The implant 24200 includes a support member 24202 and a retention member24212 movably coupled to the support member 24202. The support member24202 has a proximal portion 24204, a distal portion 24206 and a sidewall 24216. The side wall 24216 defines a lumen 24208 having alongitudinal axis L_(A). As shown, at least a portion of the outersurface of the side wall 24216 is in contact with and/or adjacent to thefirst spinous process SP1 and/or the second spinous process SP2 when thesupport member 24202 is disposed between the first spinous process SP1and the second spinous process SP2. In this manner, the implant 24200can maintain a minimal spacing between the adjacent spinous processesSP1 and SP2 during extension of the spinal column while allowing flexionof the spinal column, as described herein.

The proximal portion 24204 of the support member 24202 includes a saddlesurface 24253 having a curved shape that can form a portion of a saddle24252, as discussed in more detail herein. The proximal portion 24204also includes a locking member 24254 disposed within the lumen 24208adjacent the side wall 24216. The distal portion 24206 of the supportmember 24202 has a curved shape to facilitate insertion of the implant24200 into the body.

The retention member 24212 has a first end portion 24230, a second endportion 24232 and a central portion 24233 disposed between the first endportion 24230 and the second end portion 24232. The central portion24233 of the retention member 24212 is disposed within the lumen 24208of the support member 24202. The second end portion 24232 includes asaddle surface 24251 having a curved shape that can form a portion of asaddle 24252, as discussed in more detail herein.

The retention member 24212 is rotatably coupled to the support member24202 such that the retention member 24212 can rotate relative to thesupport member 24202 about an axis of rotation L_(R) substantiallynormal to the longitudinal axis L_(A). As indicated by the arrows GG inFIGS. 122 and 123, the retention member 24212 can rotate relative to thesupport member 24202 between a first position (FIGS. 118-120) and asecond position (FIGS. 121-123). When the retention member 24212 is inthe first position, the implant 24200 can be inserted such that at leasta portion of the side wall 24216 of the support member 24202 is disposedbetween the first spinous process SP1 and the second spinous processSP2. When the retention member 24212 is in the second position, theretention member 24212 limits movement of the support member 24202 alongthe longitudinal axis L_(A) and relative to the adjacent spinousprocesses SP1 and SP2. The second end portion 24232 of the retentionmember 24212 can limit movement of the support member 24202, forexample, by contacting and/or engaging the spinous processes SP1.

As shown in FIGS. 119 and 120, when the retention member 24212 is in thefirst position, the second end portion 24232 of the retention member24212 is disposed within the lumen 24208 of the support member 24202.When the retention member 24212 is in the first position, the implant24200 can be inserted such that a portion of the support member 22202 isdisposed between the first spinous process SP1 and the second spinousprocess SP2.

As shown in FIGS. 121-123, when the retention member 24212 is in thesecond position, the second end portion 24232 is disposed through anopening 24209 in the side wall 24208 and outside of the distal endportion 24206 of the support member 24202. When the retention member24212 is in the second position, the outer surface of the side wall22216 of the support member 24202 and the saddle surface 22251 of thesecond end portion 24232 of the retention member 24212 collectively forma portion of a saddle 24252 configured to receive a portion of thespinous process SP1. The saddle 24252 can receive and/or engage aportion of the spinous process SP1 and/or its surrounding tissue tolimit movement of the support member 24202 along the longitudinal axisL_(A) and relative to the spinous processes SP1 and SP2. In someembodiments, the saddle 24252 and/or the saddle surface 24251 can have acurved surface that substantially corresponds to a shape and/or a sizeof the spinous process SP1. In some embodiments, the shape and/or sizeof the saddle surface 24251 can be configured to more evenly distributeforces between the saddle 24252 and the spinous process SP1. In someembodiments, the saddle surface 24251 and the outer surface of the sidewall 24216 of the can form a substantially continuous surface.

Moreover, when the retention member 24212 is in the second position, thefirst end portion 24230 of the retention member 24212 engages with thelocking member 24254 to maintain the retention member 24212 in thesecond position. In some embodiments, the locking member 24254 can beconfigured to temporarily maintain the retention member 24212 in thesecond position. In other embodiments, the locking member 24254 can beconfigured to fixedly maintain the retention member 24212 in the secondposition. In some embodiments, the locking member 24254 can be, forexample, a protrusion defining a recess configured to receive and/orreleasably retain the first end portion 24230 of the retention member24212. In other embodiments, the locking member 24254 can bemonolithically formed as part of the side wall 24216. In suchembodiments, for example, the locking member 24254 can be a recessconfigured to matingly receive (e.g., via an interference fit) the firstend portion 24230 of the retention member 24212 to maintain theretention member 24212 in the second position.

Said another way, when the retention member 24212 is in the firstposition, a cross-sectional area A₂ of the second end portion 24232 ofthe retention member 24212 is within a cross-sectional area A₁ of thesupport member 24202 when projected on a plane substantially normal tothe longitudinal axis L_(A) (see FIG. 120). When the retention member24212 is in the second position, at least a portion of thecross-sectional area A₂ of the retention member 24212 is outside of thecross-sectional area A₁ of the support member 24202 when projected on aplane substantially normal to the longitudinal axis L_(A) (see FIG.123). Although the cross sectional area A₂ of the retention member 24212and the cross-sectional area A₁ of the support member 24202 are shown asbeing within a plane normal to the longitudinal axis L_(A) when viewedfrom a lateral view (e.g., FIGS. 120 and 123), the cross sectional areasA₂ and A₁ can be within a plane normal to the longitudinal axis L_(A)when viewed from a posterior view (e.g., FIGS. 119 and 122).

In some embodiments, the implant 24200 can include a biasing member,such as, for example, a torsional spring, disposed between the retentionmember 24212 and the support member 24202. In this manner, the retentionmember 24212 can be biased in the second position (i.e., such that thesecond end portion 24232 of the retention member 24212 is maintained inengagement with the first spinous process SP1 and/or its surroundingtissue). In other embodiments, the retention member 24212 can be biasedin the first position (i.e., such that the second end portion 24232 ofthe retention member 24212 is maintained within the lumen 24208 of thesupport member 24202).

Although the first end portion 24230 of the retention member 24212 andthe second end portion 24232 of the retention member 24212 are shown asbeing within the lumen 24208 of the support member 24202 when theretention member 24212 is in the first position, in other embodiments,at least a portion of the first end portion 24230 and/or the second endportion 24232 can be disposed outside of the support member 24202 whenthe retention member 24212 is in the first position. For example, insome embodiments, a second end portion of a retention member can extendoutside of a distal end portion of a support member along a longitudinalaxis of the support member when the retention member is in a firstposition. In such embodiments, for example, a cross-sectional area ofthe second end portion of the retention member can be within across-sectional area of the support member when projected on a planesubstantially normal to the longitudinal axis and when the retentionmember is in the first position, as described above.

Although the implant 24200 is shown and described as including aretention member 24212, in other embodiments, an implant can includemultiple retention members. For example, FIGS. 124-127 show an implant24300 according to an embodiment of the invention in a firstconfiguration (FIGS. 124 and 125) and a second configuration (FIGS. 126and 127). The implant 24300 includes a support member 24302, a firstretention member 24312 and a second retention member 24310. The firstretention member 24312 and the second retention member 24310 arerotatably coupled to the support member by a pin 24309.

As described above, the support member 24302 has a proximal portion24304, a distal portion 24306 and a side wall 24316. The side wall 24316defines a lumen 24308 having a longitudinal axis L_(A). As shown, atleast a portion of the outer surface of the side wall 24316 is incontact the first spinous process SP1 and/or the second spinous processSP2 when the support member 24302 is disposed between the first spinousprocess SP1 and the second spinous process SP2.

The first retention member 24312 has a proximal end portion 24330, adistal end portion 24332 and a central portion 24333 disposed betweenthe proximal end portion 24330 and the distal end portion 24332. Thecentral portion 24333 of the first retention member 24312 is disposedwithin the lumen 24308 of the support member 24302. The proximal endportion 24330 of the first retention member 24312 and the distal endportion 24332 of the first retention member 24312 are disposed outsideof the lumen 24308. The distal end portion 24332 of the first retentionmember 24312 has a curved shape (e.g., a tapered end portion) tofacilitate insertion of the implant 24300 into the body. The distal endportion 24332 of the first retention member 24312 also includes a tip24335 to facilitate insertion of the implant 24300 into the body. Insome embodiments, for example, the distal end portion 24332 of the firstretention member 24312 can displace a bodily tissue when the implant24300 is inserted into the body. In some embodiments, the distal endportion 24332 of the first retention member 24312 can dilate a bodilytissue, such as the supraspinous ligament, when the implant 24300 isinserted into the body. In some embodiments, the distal end portion24332 of the first retention member 24312 can distract a space betweenadjacent spinous processes when the implant 24300 is inserted into thebody.

Similarly, the second retention member 24310 (not shown in FIG. 111) hasa proximal end portion 24340, a distal end portion 24342 and a centralportion 24343 disposed between the proximal end portion 24340 and thedistal end portion 24342. The central portion 24343 second retentionmember 24310 is disposed within the lumen 24308 of the support member24302. The proximal end portion 24340 of the second retention member24310 and the distal end portion 24342 of the second retention member24310 are disposed outside of the lumen 24308. The distal end portion24342 of the second retention member 24310 has a curved shape (e.g., atapered end portion) to facilitate insertion of the implant 24300 intothe body.

The distal end portion 24342 of the second retention member 24310 alsoincludes a tip 24345 to facilitate insertion of the implant 24300 intothe body. In some embodiments, for example, the distal end portion 24342of the second retention member 24310 can displace a bodily tissue whenthe implant 24300 is inserted into the body. In some embodiments, thedistal end portion 24342 of the second retention member 24310 can dilatea bodily tissue, such as the supraspinous ligament, when the implant24300 is inserted into the body. In some embodiments, the distal endportion 24342 of the second retention member 24310 can distract a spacebetween adjacent spinous processes when the implant 24300 is insertedinto the body.

In some embodiments, the shape of the distal end portion 24342 of thesecond retention member 24310 can be similar (e.g., a mirror image) tothe shape of the distal end portion 24332 of the first retention member24312. Said another way, in some embodiments, the distal end portion24342 of the second retention member 24310 and the distal end portion24332 of the first retention member 24312 can cooperatively form asubstantially continuous surface.

The first retention member 24312 and the second retention member 24310are rotatably coupled to the support member 24302 about an axis ofrotation L_(R) substantially normal to the longitudinal axis L_(A). Asindicated by the arrows HH in FIGS. 126 and 127, the first retentionmember 24312 and/or the second retention member 24310 can rotaterelative to the support member 24202 to place the implant 24300 in afirst configuration (FIGS. 124 and 125) and a second configuration(FIGS. 126 and 127). When in the first configuration, the implant 24300can be inserted such that at least a portion of the side wall 24316 ofthe support member 24302 is disposed between the first spinous processSP1 and the second spinous process SP2. When in the secondconfiguration, first retention member 24312 and/or the second retentionmember 24310 limit lateral movement of the support member 24302 alongthe longitudinal axis L_(A) and relative to the adjacent spinousprocesses SP1 and SP2.

As shown in FIGS. 124 and 125, when the implant 24300 is in the firstconfiguration, the outer surface of the proximal end portion 24330 ofthe first retention member 24312 is flush with the outer surface 24316of the support member 24302 (i.e., the outer surface of the proximal endportion 24330 is spaced apart from the outer surface 24316 of supportmember 24302 by a nominal gap along a direction normal to thelongitudinal axis L_(A)). Additionally, the outer surface of the distalend portion 24332 of the first retention member 24312 is flush with theouter surface 24316 of the support member 24302 (i.e., the outer surfaceof the distal end portion 24332 is spaced apart from the outer surface24316 of support member 24302 by a nominal gap along a direction normalto the longitudinal axis L_(A)). Said another way, when the implant24300 is in the first configuration, the proximal end portion 24330 ofthe first retention member 24312, the distal end portion 24332 of thefirst retention member 24312 and the outer surface 24316 of the supportmember 24302 collectively form a substantially continuous surface.

Similarly, when the implant 24300 is in the first configuration, theouter surface of the proximal end portion 24340 of the second retentionmember 24310 is flush with the outer surface 24316 of the support member24302 (i.e., the outer surface of the proximal end portion 24340 isspaced apart from the outer surface 24316 of support member 24302 by anominal gap along an offset axis L_(O) normal to the longitudinal axisL_(A) and substantially normal to the axis of rotation L_(R)).Additionally, the outer surface of the distal end portion 24342 of thesecond retention member 24310 is flush with the outer surface 24316 ofthe support member 24302 (i.e., the outer surface of the distal endportion 24342 is spaced apart from the outer surface 24316 of supportmember 24302 by a nominal gap along the offset axis L_(O)). Said anotherway, when the implant 24300 is in the first configuration, the proximalend portion 24340 of the second retention member 24310, the distal endportion 24342 of the second retention member 24310 and the outer surface24316 of the support member 24302 collectively form a substantiallycontinuous surface.

As shown in FIGS. 126 and 127, when the implant 24300 is in the secondconfiguration, the outermost edge of the proximal end portion 24330 ofthe first retention member 24312 is spaced apart from the outer surface24316 of the support member 24302 by a distance Y₅ along the offset axisL_(O). The distance Y₅ is such that the distance between the outermostedge of the proximal end portion 24330 and the longitudinal axis L_(A)is greater than the distance between the outer surface 24316 of thesupport member 24302 and the longitudinal axis L_(A) (i.e., the proximalend portion 24330 of the first retention member 24312 is “outside” theouter surface 24316 of the support member 24302 relative to thelongitudinal axis L_(A)).

Similarly, when the implant 24300 is in the second configuration, theoutermost edge of the distal end portion 24332 of the first retentionmember 24312 is spaced apart from the outer surface 24316 of the supportmember 24302 by a distance Y₆ along the offset axis L_(O). The distanceY₆ is such that the distance between the outermost edge of the distalend portion 24332 and the longitudinal axis L_(A) is greater than thedistance between the outer surface 24316 of the support member 24302 andthe longitudinal axis L_(A) (i.e., the distal end portion 24332 of thefirst retention member 24312 is “outside” the outer surface 24316 of thesupport member 24302 relative to the longitudinal axis L_(A)). In thismanner, when the implant 24300 is in the second configuration, theproximal end portion 24330 of the first retention member 24312 and/orthe distal end portion 24332 of the first retention member 24312 cancontact the first spinous process SP1, the second spinous process SP2and/or the surrounding tissue to limit lateral movement of the supportmember 24302 relative to the spinous processes SP1 and SP2.

Similarly, when the implant 24300 is in the second configuration, theoutermost edge of the proximal end portion 24340 of the second retentionmember 24310 is spaced apart from the outer surface 24316 of the supportmember 24302 by a distance Y₇ along the offset axis L_(O). Said anotherway, the proximal end portion 24340 of the second retention member 24312is “outside” the outer surface 24316 of the support member 24302relative to the longitudinal axis L_(A). The outermost edge of thedistal end portion 24342 of the second retention member 24310 is spacedapart from the outer surface 24316 of the support member 24302 by adistance Y₈ along the offset axis L_(O). Said another way, the distalend portion 24342 of the second retention member 24310 is “outside” theouter surface 24316 of the support member 24302 relative to thelongitudinal axis L_(A). In this manner, when the implant 24300 is inthe second configuration, the proximal end portion 24340 of the secondretention member 24310 and/or the distal end portion 24342 of the secondretention member 24310 can contact the first spinous process SP1, thesecond spinous process SP2 and/or the surrounding tissue to limitlateral movement of the support member 24302 relative to the spinousprocesses SP1 and SP2.

In some embodiments, the first retention member 24312 and the secondretention member 24310 can be moved relative to the support member 24302serially. In other embodiments, the first retention member 24312 and thesecond retention member 24310 can be moved relative to the supportmember 24302 simultaneously. In yet other embodiments, only one of thefirst retention member 24312 or the second retention member 24310 can bemoved relative to the support member 24302.

FIGS. 128 and 129 show an implant 24400 according to an embodiment ofthe invention in a first configuration (FIG. 128) and a secondconfiguration (FIG. 129). The implant 24400 includes a first elongatemember 24412 and a second elongate member 24410. As shown, the implant24400 is configured to be disposed between a first spinous process SP1and a second spinous process SP2 to maintain a minimal spacing betweenthe spinous processes during extension of the spinal column. The firstelongate member 24412 and the second elongate member 24410 are rotatablycoupled together by a pin 24409.

The first elongate member 24412 has a proximal end portion 24430 and adistal end portion 24432 and defines a longitudinal axis L_(A1). Thedistal end portion 24432 of the first elongate member 24412 has a curvedshape (e.g., a tapered end portion) to facilitate insertion of theimplant 24400 into a body. The distal end portion 24432 of the firstretention member 24412 also includes a tip 24435 to facilitate insertionof the implant 24400 into the body. In some embodiments, for example,the distal end portion 24432 of the first retention member 24412 candisplace a bodily tissue when the implant 24400 is inserted into thebody. In some embodiments, the distal end portion 24432 of the firstretention member 24412 can dilate a bodily tissue, such as thesupraspinous ligament, when the implant 24400 is inserted into the body.In some embodiments, the distal end portion 24432 of the first retentionmember 24412 can distract a space between adjacent spinous processeswhen the implant 24400 is inserted into the body.

The first elongate member 24412 also has a first surface 24436 and asecond surface 24437 opposite the first surface 24436. As described inmore detail herein, the first surface 24436 and the second surface 24437are configured to contact and/or engage the first spinous process SP1and/or the second spinous process SP2, respectively to limit movement ofthe implant 24400 along the longitudinal axis L_(A1) and relative to theadjacent spinous processes SP1 and SP2. Although the first surface 24436and the second surface 24437 are shown and described as beingsubstantially parallel to each other and substantially parallel to thelongitudinal axis L_(A1), in other embodiments, the first surface 24436and/or the second surface 24437 can be angularly offset from each otherand/or angularly offset from the longitudinal axis L_(A1). Similarly,although the first surface 24436 and the second surface 24437 are shownas being linear when viewed from the posterior view, in someembodiments, the first surface 24436 and/or the second surface 24437 canhave a non-linear shape.

Similarly, as shown in FIG. 129, the second elongate member 24410 alsohas a proximal end portion 24440 and a distal end portion 24442 anddefines a longitudinal axis L_(A2). The distal end portion 24442 of thesecond elongate member 24410 has a curved shape (e.g., a tapered endportion) to facilitate insertion of the implant 24400 into the body. Thedistal end portion 24442 of the second retention member 24410 alsoincludes a tip 24445 to facilitate insertion of the implant 24400 intothe body. In some embodiments, for example, the distal end portion 24442of the second retention member 24410 can displace a bodily tissue whenthe implant 24400 is inserted into the body. In some embodiments, thedistal end portion 24442 of the second retention member 24410 can dilatea bodily tissue, such as the supraspinous ligament, when the implant24400 is inserted into the body. In some embodiments, the distal endportion 24442 of the second retention member 24410 can distract a spacebetween adjacent spinous processes when the implant 24400 is insertedinto the body.

The second elongate member 24410 also has a first surface 24446 and asecond surface 24447 opposite the first surface 24446. As described inmore detail herein, the first surface 24446 and the second surface 24447are configured to contact and/or engage the first spinous process SP1and the second spinous process SP2, respectively, either directly orindirectly, to limit movement of the implant 24400 along thelongitudinal axis L_(A1) and relative to the adjacent spinous processesSP1 and SP2. Although the first surface 24446 and the second surface24447 are shown and described as being substantially parallel to eachother and substantially parallel to the longitudinal axis L_(A2), inother embodiments, the first surface 24446 and/or the second surface24447 can be angularly offset from each other and/or angularly offsetfrom the longitudinal axis L_(A2). Similarly, although the first surface24446 and the second surface 24447 are shown as being linear when viewedfrom the posterior view, in some embodiments, the first surface 24446and/or the second surface 24447 can have a non-linear shape.

As indicated by the arrow II in FIG. 129, the first elongate member24412 and the second elongate member 24410 can rotate relative to eachother about an axis of rotation substantially normal to the longitudinalaxis L_(A) to move the implant 24400 between a first configuration (FIG.128) and a second configuration (FIG. 129). When the implant 24400 is inthe first configuration, the longitudinal axis L_(A1) of the firstelongate member 24412 is substantially parallel to the longitudinal axisL_(A2) of the second elongate member 24410. Similarly stated, when theimplant 24400 is in the first configuration, the first surface 24436 ofthe first elongate member 24412 is aligned with the first surface 24446of the second elongate member 24410 (i.e., the first surface 24436 andthe first surface 24446 form a substantially continuous surface) and thesecond surface 24437 of the first elongate member 24412 is aligned withthe second surface 24447 of the second elongate member 24410 (i.e., thesecond surface 24437 and the second surface 24447 form a substantiallycontinuous surface). Accordingly, when in the first configuration, theimplant 24400 can be disposed between the first spinous process SP1 andthe second spinous process SP2.

As shown in FIG. 129, when the implant 24400 is in the secondconfiguration, the longitudinal axis L_(A1) of the first elongate member24412 intersects the longitudinal axis L_(A2) of the second elongatemember 24410 at an angle Θ. Moreover, when the implant 24400 is in thesecond configuration, the first surface 24436 of the first elongatemember 24412 and the first surface 24446 of the second elongate member24410 collectively form a portion of a first saddle 24452 configured toreceive a portion of the spinous process SP1. Similarly, the secondsurface 24437 of the first elongate member 24412 and the second surface24447 of the second elongate member 24410 collectively form a portion ofa second saddle 24453 configured to receive a portion of the spinousprocess SP2. The first saddle 24452 and the second saddle 24453 can beof any suitable shape and size, as discussed above. In this manner, whenthe implant 24400 is in the second configuration, the first saddle 24452and/or the second saddle 24453 limit movement of the implant relative tothe adjacent spinous processes SP1 and SP2.

FIG. 130 shows a method 25100 according to an embodiment of theinvention. The method includes disposing at least a portion of animplant between a first spinous process and a second spinous process,23104. The implant includes a support member and a retention memberrotatably coupled to the support member. The implant can be any suitableimplant of the types shown and described above, such as for example, theimplant 24100.

In some embodiments, the disposing can include inserting the implantpercutaneously via a lateral access path. In some embodiments, thedisposing can include inserting the implant using a curved tool and/or aguide member, as described herein. In some embodiments, the method caninclude optionally distracting the adjacent spinous processes before thedisposing, 25102.

The retention member of the implant is rotated relative to the supportmember from a first position to a second position such that a first endportion of the retention member is disposed outside of a proximal endportion of the support member and a second end portion of the retentionmember is disposed outside a distal end portion of the support member,25106. In this manner, the first end portion of the retention member andthe second end portion of the retention member can cooperatively limitmovement of the support member along the longitudinal axis and relativeto the first spinous process and the second spinous process. In someembodiments, the retention member can be rotated about an axissubstantially normal to a longitudinal axis of the support member.

In some embodiments, the method can include optionally locking theretention member in the second position, 25108. The locking can include,for example, moving a portion of the retention member into engagementwith a locking member, as described above.

FIG. 131 shows a method 25200 according to an embodiment of theinvention. The method includes disposing at least a portion of animplant between a first spinous process and a second spinous process,25204. The implant includes a first elongate member and a secondelongate member rotatably coupled to the first elongate member. Theimplant can be any suitable implant of the types shown and describedabove, such as for example, the implant 24400.

In some embodiments, the disposing can include inserting the implantpercutaneously via a lateral access path. In some embodiments, thedisposing can include inserting the implant using a curved tool and/or aguide member, as described herein. In some embodiments, the method caninclude optionally distracting the adjacent spinous processes before thedisposing, 25202.

The second elongate member is rotated relative to the first elongatemember about an axis substantially normal to a longitudinal axis of thefirst elongate member from a first position to a second position suchthat a portion of the first elongate member and a portion of the secondelongate member engage the first spinous process, 25206. In this manner,the first elongate member and the second elongate member cooperativelylimit movement of the first elongate member along the longitudinal axisand relative to the first spinous process and the second spinousprocess.

In some embodiments, the method can include optionally maintaining theposition of the second elongate member relative to the first elongatemember after the rotating, 25208. The maintaining can include, forexample, moving a portion of the first elongate member and/or a portionof the second elongate member into engagement with a locking member, asdescribed above.

FIG. 132 is a schematic illustration of an example of a medical devicethat can be used to perform the methods described herein. A medicaldevice can include an implant, a guide member and/or an insertion tool,as described herein. The various components of the medical device can beprovided in some embodiments, for example, as a kit. Such a kit caninclude one or more implants, one or more guide members, and/or one ormore insertion tools as described herein. A medical device 26100includes an implant 26120 and a guide member 26130 that can bereleasably coupled to the implant 26120. The guide member 26130 can bepercutaneously inserted into a body and the implant 26120 can beinserted into the body and moved within the body using an insertion tool26140 that can be releasably coupled to the implant 26120. The insertiontool 26140 can be, for example, coupled to a proximal end portion of theimplant 26120. The insertion tool 26140 can apply a longitudinal forceto a proximal end of the implant 26120 to move the implant 26120 througha portion of a body. In some embodiments, the medical device 26100 canbe inserted through a cannula (not shown). The guide member 26130 can bereleasably coupled to a distal end portion of the implant 26120 and canbe used to guide the implant 26120 as the implant 26120 is moved by theinsertion tool 26140. For example, the guide member 26130 can lead theimplant 26120 along a path defined by a shape of the guide member 26130as described in more detail below.

The guide member 26130 can include a distal end having a sharp tip (notshown in FIG. 132) that can be percutaneously inserted into a bodythrough an exterior location on the body. The guide member 26130 canhave a curved shape to allow the guide member 26130 to define a curvedpath as the guide member 26130 is maneuvered through a body. A proximalend portion of the guide member 26130 can have a connector or connectorportion configured to releasably couple the guide member 26130 to theimplant 26120. A separate connector member can be coupled to the guidemember 26130, or the guide member 26130 can have a connector portionformed monolithically with the guide member 26130. For example, theguide member 26130 can include a threaded portion configured tothreadedly couple to a threaded portion of a distal end portion of theimplant 26120. In other embodiments, a proximal end portion of the guidemember 26130 can include a key member (not shown) that can be receivedin, and releasably locked, within a keyway or opening at a distal endportion of the implant 26120. In some embodiments, a proximal endportion of the guide member 26130 is received within an opening in thedistal end portion of the implant 26120 and held in place within theopening, in part, by a longitudinal force exerted on the implant 26120by an insertion tool 26140.

The guide member 26130 can be formed, for example, as a flexible wire ora flexible needle having a lumen there through. The guide member can beformed such that it is sufficiently flexible about an axis normal to alongitudinal axis of the guide member 26130 and is sufficiently rigidwhen a force along the longitudinal axis such that the guide member26130 substantially maintains its shape when percutaneously insertedinto a body.

The insertion tool 26140 includes a distal end portion configured to bereleasably coupled to the implant 26120. For example, the distal endportion of the insertion tool 26140 can define an opening and aninterior space that can receive the proximal end portion of the implant26120 therein. The proximal end portion of the implant 26120 can besized to fit within the interior space of the distal end portion of theinsertion tool 26140. When the insertion tool 26140 moves within a bodyin a direction toward the implant 26120, the implant 26120 will move inthe same direction, but when the insertion tool 26140 is moved in anopposite direction, away from the implant 26120, the insertion tool26140 will be removed from the proximal end portion of the implant26120.

The insertion tool 26140 can have various different, shapes, sizes andconfigurations and include different coupling means to releasably couplethe insertion tool 26140 to the implant 26120. Likewise, the proximalend portion of the implant 26120 can include various coupling means forcoupling the implant 26120 to an insertion tool 26140. For example, insome embodiments, the insertion tool can be releasably coupled to theimplant via a quick-connect coupling as shown and described in U.S.patent application Ser. No. 11/693,496, incorporated herein byreference. In some embodiments, the insertion tool is releasably coupledto the implant via a locking member disposed on the insertion tool alsoas shown and described in the above-mentioned application. In someembodiments, the insertion tool is releasably coupled to the implantusing a key and keyway as shown and described herein with reference toFIGS. 15 and 16. For example, the distal end portion of the implant caninclude multiple notches that can matingly receive correspondingprotrusions on the distal end portion of the insertion tool.

In use, a distal end of the guide member 26130 is percutaneouslyinserted into a body through a first location on the body. The implant26120 can be coupled to the guide member 26130 before or after at leastthe distal end of the guide member 26130 has been inserted into thebody. For example, the guide member 26130 can be inserted partially intothe body and then the implant 26120 inserted into the body thereafter.

In some embodiments, the guide member 26130 has a length such that theguide member 26130 can be inserted into the body at a first location,and moved or pushed through the body along a curved path until thedistal end of the guide member 26130 exits the body at a secondlocation. In such an embodiment, the implant 26120 is inserted into thebody after the distal end of the guide member 26130 exits the body atthe second location.

In some embodiments, the distal end of the guide member 26130 isinserted through a first opening in a body at a first distance from acenterline of the body. The guide member 26130 can then be advanced,either with or without the implant 26120 being advanced within the body,until the distal end of the guide member 26130 exits the body at asecond opening at a second distance from the centerline of the body andon a second side of the centerline of the body. In some embodiments, thefirst distance is substantially equal to the second distance. In otherembodiments, the first distance is not equal to the second distance.

With the distal end portion of the implant 26120 coupled to the proximalend portion of the guide member 26130, the insertion tool 26140 can beused to push or advance the implant 26120 through the body to a selectedposition within the body. In some embodiments, an imaging device is usedto assist in the positioning of the implant 26120 at a desired locationwithin the body. As the implant 26120 is advanced in the body, theimplant 26120 will move or advance the guide member 26130 through thebody along a path defined by the guide member 26130. The implant 26120can be moved, for example, to a position between two adjacent bonestructures, such as, between two adjacent spinous processes. In doingso, the distal end of the guide member 26130 will exit the body at asecond location, if not already exited prior to inserting or moving theimplant 26120. After the implant 26120 is positioned in the desiredlocation within the body (e.g., between bone structures), the guidemember 26130 can be released from the implant 26120. For example, thedistal end of the guide member 26130 positioned outside of the body atthe second location can be grasped, and the releasable coupling betweenthe guide member 26130 and the implant 26120 can be decoupled to releasethe guide member 26130 from the implant 26120.

The insertion tool 26140 can also be released from the implant 26120 andremoved from the body before, after or simultaneously with the removalof the guide member 26130. After removing both the guide member 26130and the insertion tool 26149, the implant 26120 will be left within thebody at the desired implantation site.

FIG. 133 is an exploded view of an embodiment of a medical deviceincluding an implant, a guide member and insertion tool. The variouscomponents of the medical device can be provided, for example, as a kit.The kit can include one or more implants, and/or one or more guidemembers, and/or one or more insertion tools. A medical device 26200includes an implant 26220 having a proximal end portion 26222 and distalend portion 26224. The distal end portion 26224 of the implant 26220defines an opening 26228. The implant 26220 also includes a threadedportion 26226 disposed at the distal end portion 26224 as illustrated inFIGS. 133 and 134.

A guide member 26230 has a proximal end portion 26236, a distal endportion 26234 and a distal end 26238 having a sharpened or taperedshape. The proximal end portion 26232 of the guide member 26230 includesa threaded portion 26236. The threaded portion 26236 is configured tomatingly couple to the corresponding threaded portion 26226 of theimplant 26220. The distal end 26238 can be percutaneously insertedthrough an exterior location of a body and passed through the body untilthe distal end 26238 exits the body at a second exterior location of thebody.

An insertion tool 26240 includes a middle portion 26242, a proximal endportion (not shown) and a distal end portion 26244. In some embodiments,the proximal end portion, the distal end portion 26244, and the middleportion 26242 are monolithically formed. In some embodiments, some orall of the proximal end portion, the distal end portion 26244, and themiddle portion 26242 are formed as separate components and coupledtogether. The distal end portion 26244 defines an opening 26248 that isin communication with an interior space 26250 as best shown in FIG. 135.The proximal end portion 26222 of the implant 26220 can be receivedthrough the opening 26248 and disposed within the interior space 26250to releasably couple the implant 26220 to the insertion tool 26240.

The guide member 26230 and the insertion tool 26240 can be used todeliver the implant 26220 to an implantation site within a body. FIGS.136 and 137 illustrate an example of a procedure to deliver the implant26220 to a location between adjacent spinous processes. As shown in FIG.136, the guide member 26230 is percutaneously inserted through a firstexterior location B1 in a body B. As described above, the implant 26220can be coupled to the guide member 26230 before or after the guidemember 26230 is inserted into a body. To couple the guide member 26230to the implant 26220, the threaded portion 26236 of the guide member26230 is rotated with respect to the mating threaded portion 26226 ofthe implant 26220. The curved shape of the guide member 26230 defines acurved path through the body as the guide member 26230 is moved throughthe body, indicated by the dashed-line path in FIG. 136. In this exampleprocedure, the path of the guide member 26230 passes between adjacentspinous processes (only the inferior spinous process S1 is shown in FIG.136). In this embodiment, the length of the guide member 26230 is suchthat the implant 26220 is still disposed outside the body B when theguide member 26230 is passed between the spinous processes.

The insertion tool 26240 is coupled to the proximal end portion of theimplant 2620 to push or move the implant 26220 through the body B, asshown in FIG. 137. FIG. 137 is a top view illustrating a view above asecond spinous process S2 superior to the spinous process S1. As theinsertion tool 26240 moves or advances the implant 26220 to a positionbetween the inferior spinous process S1 and the superior spinous processS2, the guide member 26230 will be advanced along the curved pathdefined by the curve of the guide member 26230. The guide member 26230will be advanced until the distal tip 26238 exits a second exteriorlocation B2 on the body B.

Once the implant 26220 is positioned in the desired location within thebody, the insertion tool 26240 can be decoupled from the implant 26220by pulling the insertion tool 26240 proximally and out of the body B.The guide member 26230 can also be removed from the implant 26220 byturning the guide member counter-clockwise to decouple the threadedcoupling between the implant 26220 and the guide member 26230. It may bedesirable to remove the guide member 26230 before removing the insertiontool 26240 so that the insertion tool 26240 can be held to stabilize theimplant 26220 while decoupling the guide member 26230 from the implant26220. After removing both the guide member 26230 and the insertion tool26240, the implant 26220 will remain implanted between the two spinousprocesses S1 and S2.

FIG. 138 illustrates an embodiment of a guide member that has sufficientlength to extend within a body between an ingress location and an egresslocation before inserting an implant into the body. A guide member 26330is shown percutaneously inserted through a first location B1 on a bodyB, passing between adjacent spinous processes (only an inferior spinousprocess S1 is shown), and a distal end 26338 of the guide member 26330exiting the body B at an exit location B2. The ingress location B1 is ata distance Y from a centerline C of the body B, and the egress locationB2 is at a distance X from the centerline C of the body B on an oppositeside of the centerline C. In this embodiment, the distance X and thedistance Y is substantially equal. In other embodiments, the distance Xand the distance Y are not equal.

As stated previously, a distal end portion of an implant (not shown) canbe releasably coupled to a proximal end portion 26332 of the guidemember 26330, either before or after the guide member 26330 has beeninserted into the body B. Although not needed for all embodiments, anoptional insertion tool (not shown) can be used to advance the implantand guide member 26330 along a curved path defined by the guide member26330 as described previously. Alternatively, after the distal end 26338is positioned outside of the egress location B2, the distal end 26338 ofthe guide member 26330 can be grasped (e.g., by hand, with forceps, orusing another instrument) and pulled such that the implant is moved(e.g., pulled) through the body B and to a desired implantation site.For example, the implant can be pulled through the body B along thecurved path defined by the guide member 26330 and is positioned betweenadjacent spinous processes.

FIGS. 139-141 illustrate another embodiment of a medical device. Amedical device 26400 includes an implant 26420 and guide member 26430.The implant 26420 and guide member 26430 are similar to the embodimentsillustrated in FIG. 133 except in this embodiment the coupling betweenthe implant 26420 and the guide member 26430 includes a key configuredto be received within a keyway. The implant 26420 has a proximal endportion 26426 and a distal end portion 26424. The distal end portion26424 defines an opening 26428 and a slot or keyway 26458, as shown inthe distal end view of the implant 26420 of FIG. 140. The slot 26458 isin fluid communication with an interior space 26460 within the implant26420. The guide member 26430 has a distal end portion 26434 thatincludes a sharp distal end or tip 26438. The guide member 26430 alsohas a proximal end portion 26432 that includes a key 26456. The key26456 can be received through the opening 26428 and the slot 26458 toreleasably couple the guide member 26430 to the implant 26420.

For example, to couple the guide member 26430 to the implant 26420, theguide member 26430 is initially turned or oriented such that the key26456 is substantially aligned with the opening 26428 and slot 26458.The key 26456 is then placed through the slot 26458 and then turned(e.g., 90 degrees) such that the key 26456 is at least partiallymisaligned with the slot 26458 and disposed within the interior region26460 of the implant 26420, as shown in FIG. 141.

After the implant 26420 coupled to the guide member 26430, the implant26420 can be inserted within a body in the same manner as describedpreviously, using an insertion tool (not shown) releasably coupled tothe proximal end portion 26426 of the implant 26420. For example, theinsertion tool can apply a longitudinal force on a proximal end of theimplant 26420 to move or advance the implant 26420 within a body. Thiswill in turn move or advance the guide member 26430 coupled to theimplant 26420. As with the previous embodiments, the implant 26420 willbe advanced along a curved path defined by the guide member 26430. Oncethe implant 26420 is positioned at an implantation site, the guidemember 26430 can be decoupled from the implant 26420 and removed fromthe body. To decouple the guide member 26430 from the implant 26420, theguide member 26430 is turned such that the key 26456 is substantiallyaligned with the slot 26458. This will allow the guide member 26430 tobe moved out of the interior region 26460 of the implant 26420 throughthe slot 26458, and removed from the body. The insertion tool can alsobe removed as previously described.

FIGS. 142 and 143 illustrate another embodiment of guide member andimplant. A medical device 26500 includes a guide member 26530 and animplant 26520. The implant 26520 and guide member 26530 are similar tothe previous embodiments, except in this embodiment, the guide member26530 is coupled to the implant 26520 in a manner similar to thecoupling between the implant 26220 and insertion tool 26240 illustratedin FIG. 143. The implant 26520 has a proximal end portion 26522 and adistal end portion 26524 that defines an opening 26528. The distal endportion 26524 includes a surface 26562 disposed within the opening26528.

The guide member 26530 has a distal end portion 26534 that includes adistal end 26538, and a proximal end portion 26532 that can be receivedwithin the opening 26528. As shown in FIG. 143, the implant 26520 can beadvanced through a body B using an insertion tool 26540 as previouslydescribed. As a force is applied by the insertion tool 26540 andtranslated to a proximal end the implant 26520 in the direction of arrowD, the implant 26520 and the guide member 26530 will be advanced along apath defined by the guide member 26530. A longitudinal force is appliedby the implant 26520 on the proximal end portion 26532 of the guidemember 26530 to move the implant 2620 in a direction toward the distalend 26538 of the guide member 26530. This force will advance the guidemember 26530 within the body, and maintain the position of the proximalend portion 26532 of the guide member 26530 within the opening 26528 ofthe implant 26520. In addition, internal walls of the implant 26520 thatdefine the opening 26528 help maintain the position of the proximal endportion 26532 of the guide member 26530 within the opening 26528 of theimplant 26520. After the implant 26520 is positioned at a desiredlocation within the body (e.g., between adjacent spinous processes), andthe distal tip 26538 of the guide member 26530 has exited the body at alocation B2, the guide member 26530 can be removed by pulling the guidemember 26530 out through the exit location 26554.

The guide members described above can be used in the deployment of avariety of different types of implants. The guide members can beconfigured to be releasably coupled to any of the implants, extensionlimiting devices, extraction devices described herein or with otherdevices not specifically described. For example, a guide member asdescribed herein can be configured to be releasably coupled to animplant 6610 illustrated with references to FIGS. 17-23. A distal endportion of the implant 6610 can be configured with an opening that canreceive a proximal end of a guide member as described herein. Variousdifferent coupling methods can also be included on an implant 6610, suchas the key and keyway coupling or the threaded coupling described above.Thus, the implants and guide members described herein are merely exampleembodiments to illustrate and described the use of a guide member in thedeployment of an implant within a body.

Further, the various coupling methods described herein to releasablycouple a guide member to a distal end portion of an implant can also beused to couple an implant to an insertion tool. Likewise, the variouscoupling methods described herein to releasably couple an implant to aninsertion tool can be used to couple a guide member to an implant. Forexample, a guide member and implant can each be configured to include aquick-connect coupling to releasably couple the guide member to theimplant. In another example, a guide member can include one or moreprotrusions configured to be received in one or more notches formed inthe distal end portion of the implant as described herein with referenceto the implant and insertion tool of FIGS. 15 and 16.

FIG. 144 is a flowchart of a method of using a guide member to deliveran implant between spinous processes. At 26890, at least a portion of aguide member as described herein is inserted percutaneously into a bodythrough at a first exterior location on the body. A distal end portionof an implant is releasably coupled to a proximal end portion of theguide member at 26891. The implant can be coupled to the guide membereither before or after the guide member is inserted into the body. At26892, an insertion tool is releasably coupled to a proximal end portionof the implant. The insertion tool can be coupled to the implant eitherbefore or after the implant is coupled to the guide member. At 26893,the insertion tool applies a force to the implant to move or advance theimplant such that the guide member is advanced within the body along apath defined by the guide member. A trajectory of the path is defined bythe shape of the guide member. For example, the guide member can have acurved shape and will define a curved path.

At 26894, the implant is positioned between adjacent bone structures,such as between a superior and inferior spinous process. The guidemember is advanced such that a distal end of the guide member exits thebody at a second location. As stated previously, the guide member can beadvanced such that a distal end of the guide member extends from thebody at a second location either before or after the implant has beeninserted into the body. Thus, the guide member can be so advancedsimultaneously with the positioning of the implant between adjacent bonestructures. After the implant is positioned between the bone structures,at 26895, the guide member is decoupled from the implant and removedfrom the body at a second location on the body. At 26896 the insertiontool is decoupled from the implant and removed from the body.

FIG. 145 illustrates a device according to another embodiment of theinvention. A measurement device 26610 can be used in conjunction with aprocedure to deliver an implant between adjacent bone structures, or aprocedure to distract adjacent bone structures, such as, for example, aprocedure to distract adjacent spinous processes as described herein.For example, the measurement device 26610 can be used to measure therelative movement between the adjacent bone structures being distractedand to measure the amount of correction achieved by a distractionprocedure. The measurement device 26610 can be used independent of animplant or other device used to distract the adjacent bone structures,and without the use of an imaging device, such as a fluoroscopy device.In addition, the measurement device 26610 is not limited to use inconjunction with any particular type of distraction or extensionlimiting device. The measurement device 26610 can also increase thereliability and accuracy of a procedure to measure the amount ofdistraction by reducing the potential variability of the interfacebetween, for example, a distraction device and an imaging device. Inaddition, the measurement device 26610 extends outside of a body, whichallows a physician to visualize the physical correction (e.g.,distraction) being made to the bone structures external from the patientrather than measuring the correction on an imaging screen. Thus, thevariability and/or error factor of the electronic interface iseliminated.

As shown in FIG. 145. the measurement device 26610 includes a firstanchor member 26664 and a second anchor member 26666 that can be coupledtogether such that the relative movement between the first anchor member26664 and the second anchor member 26666 can be viewed and/or measured.The first anchor 26664 includes a first portion 26668 that defines anopening 26670, and a second portion 26672 that can be driven or nailedto a bone structure. The second anchor member 26666 includes a firstportion 26674 that can be received through the opening 26670 of thefirst anchor member 26664, and a second portion 26676 that can be drivenor nailed to a bone structure. The second portion 26672 of the firstanchor member 26664, and the second portion 26676 of the second anchormember 26666 can alternatively include a threaded portion to screw orthreadedly couple each of the second portion 26672 and the secondportion 26676 to a bone structure.

The first portion 26674 of the second anchor member 26666 can move orslide relative to the first anchor member 26664 via the opening 26670.The second anchor member 26666 also includes markings 26678 along alongitudinal length of the first portion 26674. The markings 26678 canbe measurement graduations and can be used to determine an amount ofmovement between the first anchor member 26664 and the second anchormember 26666 as described in more detail below.

FIG. 146 illustrates an example use of the measurement device 26610 tomeasure the distraction achieved between adjacent spinous processesafter insertion and/or use of a distraction device such as an implant ordistraction device as described herein. Prior to the insertion of thedistraction device, the second portion 26672 of first anchor member26664 is percutaneously inserted through a first opening B1 of a body B,and removably secured to a first spinous process S1 (e.g., nailed ordriven into the first spinous process S1). The first portion 26674 ofthe second anchor member 26666 is disposed through the opening 26670 ofthe first anchor member 26664, and the second portion 26676 of thesecond anchor member 26666 is inserted through an opening B2 of the bodyB, and removably secured to a second spinous process S2 (e.g., nailed ordriven into the second spinous process S2). The dashed-line illustrationof a portion of the first anchor member 26664 and a portion of thesecond anchor member 26666 is shown to indicate a position of the firstspinous process S1 and the second spinous process S2, before beingdistracted. A first measurement can be taken using the markings 26678.For example, a first measurement can be taken where the 26674 passesthrough the opening 26670 of the first anchor member 26664 as indicatedat 26684, prior to distracting the adjacent spinous processes.

A distraction device such as, for example, an implant or distractiondevice described herein (not shown) can be placed between the spinousprocess S1 and the spinous process S2. A force F can be exerted on thespinous process S1 and the spinous process S2 to move the first spinousprocess S1 and second spinous process S2 apart a distance X. A secondmeasurement can be taken where the first portion 26674 of the secondanchor member 26666 passes through the opening 26670 of the first anchormember 26664 at 26686, after distracting the adjacent spinous processes.The distance X can be calculated as the difference between the firstmeasurement and the second measurement.

FIG. 147 illustrates a measurement device according to anotherembodiment. A measurement device 26710 is similar to a template that canbe used to determine the size of an implant that is appropriate forimplantation in the space between bone structures. For example, themeasurement device 26710 can be used to measure the size of an implantto be placed between adjacent spinous processes. Rather thanapproximating the size of an appropriate implant when, for example, apatient is under anesthesia and unable to provide feedback to thephysician as to whether their pain has been relieved, the measurementdevice 26710 can be used when the patient is awake. For example, anx-ray of a patient's spine can be taken while the patient bends over. Adetermination can be made as to the amount of distraction needed, basedon the level of pain relief the patient feels as the patient bends over.The physician can place the measurement device 26710 adjacent an x-rayimage, to measure the amount of distraction necessary and the size ofimplant needed to be placed between the adjacent spinous processes.

The measurement device 26710 is a substantially planar device similar toa ruler or template. The measurement device 26710 can be formed oftransparent material to allow the physician to see an image, forexample, from an x-ray, through. The measurement device 26710 includesmarkings 26778, and defines multiple openings 26788. The markings 26778are measurement graduations that can be scaled to correspond to the typeof image (e.g., x-ray) being used during the measurement process. Theopenings 26788 can be sized, for example, to correspond to various sizesof interspinous implants. The scale of the markings 26788 to the size ofthe openings 26788 can vary depending on the particular imaging device.For example, the markings 26788 used to measure the image can be a 1:1scale to the dimensions used for the openings 26788. For example, for a1:1 scale, 10 graduations of the markings 26788 equals a 10 mm diameteropening 26788. Other scales can alternatively be used.

FIG. 148 illustrates an example use of the measurement device 26710. Themeasurement device 26710 is placed adjacent to, or in contact with animage I, which is a side view of a portion of a patient's spine. Avisual of the spinal components can be viewed through the measurementdevice 26710. To determine a size of an implant needed to be placedbetween a spinous process S1 and a spinous process S2, a distancebetween the spinous processes is measured using the markings 26778. Thesize of implant appropriate for implantation is then determined by theopening 26788 that corresponds to the measurement of the markings 26778.In the example shown in FIG. 148, a distance between the spinousprocesses S1 and S2 is approximately 6 graduations as indicated onmarkings 26778, and the appropriate implant size would be 8 mm asindicated by the opening 26788 that corresponds to the 6 mm graduation.

FIGS. 149-152 are schematic illustrations of an implant 27100 accordingto an embodiment of the invention in a first configuration, a secondconfiguration, a third configuration and a fourth configuration,respectively. The implant 27100 includes a support member 27102, a firstretention member 27112 and a second retention member 27110. The supportmember 27102 has a first end portion 27106, a second end portion 27104and an outer surface 27116. As shown in FIGS. 151 and 152, at least aportion of the outer surface 27116 is configured to be disposed betweena first spinous process SP1 and a second spinous process SP2.

The first retention member 27112 has a first end portion 27130, a secondend portion 27132 and defines a longitudinal axis L_(A1). The first endportion 27130 of the first retention member 27112 has an inner surface27136 and an outer surface 27137 opposite the inner surface 27136.Similarly, the second end portion 27132 of the first retention member27112 has an inner surface 27138 and an outer surface 27139 opposite theinner surface 27138. Although the inner surface 27136 of the first endportion 27130 and the inner surface 27138 of the second end portion27132 are shown as forming a continuous, co-planar surface, in otherembodiments, the inner surface 27136 of the first end portion 27130 canbe discontinuous or in a plane different than the inner surface 27138 ofthe second end portion 27132. Similarly, in some embodiments, the outersurface 27137 of the first end portion 27130 can be discontinuous or ina plane different than the outer surface 27139 of the second end portion27132.

The second retention member 27110 has a first end portion 27140, asecond end portion 27142 and defines a longitudinal axis L_(A2). Thefirst end portion 27140 of the second retention member 27110 has aninner surface 27146 and an outer surface 27147 opposite the innersurface 27146. Similarly, the second end portion 27142 of the secondretention member 27110 has an inner surface 27148 and an outer surface27149 opposite the inner surface 27148. Although the inner surface 27146of the first end portion 27140 and the inner surface 27148 of the secondend portion 27142 are shown as forming a continuous, co-planar surface,in other embodiments, the inner surface 27146 of the first end portion27140 can be discontinuous or in a plane different than the innersurface 27148 of the second end portion 27142. Similarly, in someembodiments, the outer surface 27147 of the first end portion 27140 canbe discontinuous or in a plane different than the outer surface 27149 ofthe second end portion 27142.

The first retention member 27112 is slidably coupled to the first endportion 27106 of the support member 27102. As indicated by the arrow PPin FIG. 152, the first retention member 27112 can translate along itslongitudinal axis L_(A1) between a first position (FIGS. 149-151) and asecond position (FIG. 152). When the first retention member 27112 is inthe first position, the first end portion 27130 is spaced apart from thesupport member 27102 and the second end portion 27132 is adjacent thefirst end portion 27106 of the support member 27102. Moreover, asdescribed in more detail herein, when the first retention member 27112is in the first position, the first end portion 27130 can contact and/orengage the first spinous process SP1 (or its associated surroundingtissue) to limit lateral movement of the support member 27102 along thelateral axis L_(L) and relative to the adjacent spinous processes SP1and SP2. When the first retention member 27112 is in the secondposition, the first end portion 27130 is spaced apart from the supportmember 27102 and the second end portion 27132 is spaced apart from thesupport member 27102. Moreover, as described in more detail herein, whenthe first retention member 27112 is in the second position, the firstend portion 27130 can contact and/or engage the first spinous processSP1 (or its associated surrounding tissue) and the second end portion27132 can contact and/or engage the second spinous process SP2 (or itsassociated surrounding tissue). In this manner, when the first retentionmember 27112 is in its second position, the first retention member 27112can limit lateral movement of the support member 27102 along the lateralaxis L_(L) and relative to the adjacent spinous processes SP1 and SP2.

Similarly, the second retention member 27110 is slidably coupled to thesecond end portion 27104 of the support member 27102. As indicated bythe arrow QQ in FIG. 152, the second retention member 27110 cantranslate along its longitudinal axis L_(A2) between a first position(FIGS. 149-151) and a second position (FIG. 152). When the secondretention member 27112 is in the first position, the first end portion27140 is spaced apart from the support member 27102 and the second endportion 27142 is adjacent the second end portion 27104 of the supportmember 27102. Moreover, as described in more detail herein, when thesecond retention member 27110 is in the first position, the first endportion 27140 can contact and/or engage the second spinous process SP2(or its associated surrounding tissue) to limit lateral movement of thesupport member 27102 along the lateral axis L_(L) and relative to theadjacent spinous processes SP1 and SP2. When the second retention member27110 is in the second position, the first end portion 27140 is spacedapart from the support member 27102 and the second end portion 27142 isspaced apart from the support member 27102. Moreover, as described inmore detail herein, when the second retention member 27110 is in thesecond position, the first end portion 27140 can contact and/or engagethe second spinous process SP2 (or its associated surrounding tissue)and the second end portion 27142 can contact and/or engage the firstspinous process SP1 (or its associated surrounding tissue). In thismanner, when the second retention member 27110 is in its secondposition, the second retention member 27110 can limit lateral movementof the support member 27102 along the lateral axis L_(L) and relative tothe adjacent spinous processes SP1 and SP2.

In use, the adjacent spinous processes SP1 and SP2 can be distractedprior to inserting the implant 27100 into the patient. An accesspassageway can be defined to allow insertion of the implant 27100. Thepassageway can have any suitable shape and can be formed by any suitablemethod, as discussed herein. After the access passageway is defined, theimplant 27100 can be inserted percutaneously along a lateral accesspassageway, as shown by the arrow NN in FIG. 149. As shown in FIG. 149,during insertion, the implant 27100 is placed in a first configurationin which the first retention member 27112 is in the first position, thesecond retention member 27110 is in the first position, the longitudinalaxis L_(A1) of the first retention member 27112 is substantiallyparallel to the lateral axis L_(L), and the longitudinal axis L_(A2) ofthe second retention member 27110 is substantially parallel to thelateral axis L_(L). The overall length of the implant 27100 (i.e., thesum of lengths L₁, L₂ and L₃ as shown in FIG. 151) is such that theimplant 27100 can be disposed between the first spinous process SP1 andthe second spinous process SP2 when the implant is in the firstconfiguration.

Although the implant 27100 is described as being inserted after anaccess passageway is defined, in some embodiments, an access passagewaycan be defined by the implant when it is being inserted. For example, insome embodiments, the first end portion 27130 of the first retentionmember 27112 can include a sharp tip suitable for defining a passageway.Similarly, in some embodiments, portions of the retention members 27112,27110 and/or the support member 27102 can be tapered such that apassageway can be defined when the implant 27100 is being inserted.

When the implant 27100 is between the first spinous process SP1 and thesecond spinous process SP2, the implant 27100 can be rotated into thesecond configuration. As shown by the arrow OO in FIG. 150, the implant27100 can be rotated relative to the adjacent spinous processes SP1 andSP2 about an axis substantially normal to a mid-line axis L_(M) definedby the spinal column. The diagonal dimension D across the support member27102 and including a portion of the first retention member 27112 andthe second retention member 27110 is such that the implant 27100 can bedisposed between the first spinous process SP1 and the second spinousprocess SP2 when the implant is in the second configuration. Saidanother way, the diagonal dimension D is sized such that the implant27100 can be rotated as shown in FIG. 150. Although the diagonaldimension D is shown as being less than the spacing between the firstspinous process SP1 and the second spinous process SP2 such that theimplant 27100 can be rotated without contacting the first spinousprocess SP1 and/or the second spinous process SP2, in other embodiments,the diagonal dimension D can be greater than the spacing between theadjacent spinous processes SP1 and SP2. In such embodiments, the implantcan distract the adjacent spinous processes SP1 and SP2 when in thesecond configuration (i.e., when rotating relative to the adjacentspinous processes SP1 and SP2).

As shown in FIG. 151, the implant 27100 can be rotated relative to theadjacent spinous processes SP1 and SP2 approximately ninety degrees intothe third configuration (i.e., the implant can be moved from the firstconfiguration shown in FIG. 149 to the third configuration shown in FIG.151). When the implant 27100 is in the third configuration, the firstretention member 27112 is in its first position and the second retentionmember 27110 is in its first position. Additionally, when the implant27100 is in the third configuration, the inner surface 27136 of thefirst end portion 27130 of the first retention member 27112 is disposedadjacent the first spinous process SP1. Said another way, when theimplant 27100 is in the third configuration, the inner surface 27136 ofthe first end portion 27130 of the first retention member 27112 isbetween the outer surface 27137 of the first end portion 27130 of thefirst retention member 27112 and the first spinous process SP1. In someembodiments, the inner surface 27136 of the first end portion 27130 cansubstantially contact a portion of the first spinous process SP1 (eitherdirectly or indirectly through surrounding tissue) when the implant27100 is in the third configuration.

Similarly, when the implant 27100 is in the third configuration, theinner surface 27146 of the first end portion 27140 of the secondretention member 27110 is disposed adjacent the second spinous processSP2. Said another way, when the implant 27100 is in the thirdconfiguration, the inner surface 27146 of the first end portion 27140 ofthe second retention member 27110 is between the outer surface 27147 ofthe first end portion 27140 of the second retention member 27110 and thesecond spinous process SP2. In some embodiments, the inner surface 27146of the first end portion 27140 can substantially contact a portion ofthe second spinous process SP2 (either directly or indirectly throughsurrounding tissue) when the implant 27100 is in the thirdconfiguration.

After the implant 27100 is placed in the third configuration, the firstretention member 27112 can be moved along its longitudinal axis L_(A1)from the first position to the second position, as indicated by thearrow PP in FIG. 152. Said another way, the first retention member 27112can be moved from the first position to the second position along anaxis substantially parallel to the mid-line axis L_(M). Similarly, thesecond retention member 27110 can be moved along its longitudinal axisL_(A2) from the first position to the second position, as indicated bythe arrow QQ in FIG. 152. Said another way, the second retention member27110 can be moved from the first position to the second position alongan axis substantially parallel to the mid-line axis L_(M). As indicatedby the arrows PP and QQ, the first retention member 27112 can be movedin a first direction (downward) and the second retention member 27110can be moved in a second direction (upward), opposite the firstdirection. In this manner, the implant can be placed into the fourthconfiguration, as shown in FIG. 152.

When the implant 27100 is in the fourth configuration, the first endportion 27130 of the first retention member 27112 is spaced apart fromthe support member 27102 and the second end portion 27132 of the firstretention member 27112 is spaced apart from the support member 27102.Moreover, when the implant 27100 is in the fourth configuration, thefirst end portion 27130 is disposed adjacent the first spinous processSP1 and the second end portion 27132 is disposed adjacent the secondspinous process SP2. Said another way, when the implant 27100 is in thefourth configuration, the inner surface 27136 of the first end portion27130 of the first retention member 27112 is between the outer surface27137 of the first end portion 27130 of the first retention member 27112and the first spinous process SP1. Similarly, the inner surface 27138 ofthe second end portion 27132 of the first retention member 27112 isbetween the outer surface 27139 of the second end portion 27132 of thefirst retention member 27112 and the second spinous process SP2. In thismanner, when the implant 27100 is in the fourth configuration, the firstretention member 27112 can limit lateral movement of the support member27102 along the lateral axis L_(L) and relative to the adjacent spinousprocesses SP1 and SP2. In some embodiments, the inner surface 27136 ofthe first end portion 27130 and/or the inner surface 27138 of the secondend portion 27132 can substantially contact a portion of the firstspinous process SP1 and/or the second spinous process SP2, respectively(either directly or indirectly through surrounding tissue) when theimplant 27100 is in the fourth configuration.

When the implant 27100 is in the fourth configuration, the first endportion 27140 of the second retention member 27110 is spaced apart fromthe support member 27102 and the second end portion 27142 of the secondretention member 27110 is spaced apart from the support member 27102.Moreover, when the implant 27100 is in the fourth configuration, thefirst end portion 27140 is disposed adjacent the second spinous processSP2 and the second end portion 27142 is disposed adjacent the firstspinous process SP1. Said another way, when the implant 27100 is in thefourth configuration, the inner surface 27146 of the first end portion27140 of the second retention member 27110 is between the outer surface27147 of the first end portion 27140 of the second retention member27110 and the second spinous process SP2. Similarly, the inner surface27148 of the second end portion 27142 of the second retention member27110 is between the outer surface 27149 of the second end portion 27142of the second retention member 27110 and the first spinous process SP1.In this manner, when the implant 27100 is in the fourth configuration,the second retention member 27110 can limit lateral movement of thesupport member 27102 along the lateral axis L_(L) and relative to theadjacent spinous processes SP1 and SP2. In some embodiments, the innersurface 27146 of the first end portion 27140 and/or the inner surface27148 of the second end portion 27142 can substantially contact aportion of the second spinous process SP2 and/or the first spinousprocess SP1, respectively (either directly or indirectly throughsurrounding tissue) when the implant 27100 is in the fourthconfiguration.

If or when it is desirable to change the position of the implant 27100and/or remove the implant 27100, the first retention member 27112 can bemoved back to its first position and the second retention member 27110can be moved back to its first position, thereby allowing the implant27100 to be rotated (in direction opposite from that indicated by thearrow OO in FIG. 150) to place the implant 27100 back in the secondconfiguration. Once the implant 27100 is in the second configuration,the implant 27100 can be repositioned and/or removed. If or when theimplant 27100 is repositioned as desired, the implant can be moved tothe fourth configuration, as described above.

In some embodiments, the first retention member 27112 and the secondretention member 27110 can be moved relative to the support member 27102serially. In other embodiments, the first retention member 27112 and thesecond retention member 27110 can be moved relative to the supportmember 27102 simultaneously. In yet other embodiments, only one of thefirst retention member 27112 or the second retention member 27110 can bemoved relative to the support member 27102.

In some embodiments, the first retention member 27112 can be temporarilymaintained in its first position and/or its second position by a lockingmechanism as shown and described above in connection with otherembodiments (see e.g., FIGS. 95-99). Similarly, in some embodiments, thefirst retention member 27112 can be biased in its first position and/orits second position by a biasing member as shown and described above inconnection with other embodiments (see e.g., FIGS. 118-123). In someembodiments, the second retention member 27110 can be temporarilymaintained in its first position and/or its second position by a lockingmechanism as shown and described above in connection with otherembodiments (see e.g., FIGS. 95-99). Similarly, in some embodiments, thesecond retention member 27110 can be biased in its first position and/orits second position by a biasing member as shown and described above inconnection with other embodiments (see e.g., FIGS. 118-123).

Although the implant 27100 is shown and described without reference toany specific dimensions, the implant 27100 can have any suitable size tobe disposed between the adjacent spinous processes SP1 and SP2 asdescribed above. In some embodiments, for example, the implant 27100 canbe sized such that the diagonal dimension D is less than the distancebetween the first spinous process SP1 and the second spinous process SP2such that the implant 27100 can be rotated without substantiallycontacting the first spinous process SP1 and/or the second spinousprocess SP2. In other embodiments, the implant 27100 can be sized suchthat the diagonal dimension D can be greater than the spacing betweenthe adjacent spinous processes SP1 and SP2.

Referring to the dimensions shown in FIG. 151, in some embodiments, forexample, the length L₃ of the support member 27102 can be between 5 mmand 16 mm. In some embodiments, the length L₃ of the support member27102 can be approximately 8 mm. In some embodiments, the length L₁ ofthe first retention member 27112 can be between 1 mm and 4 mm. In someembodiments, the length L₁ of the first retention member 27112 can beapproximately 2 mm. Similarly, in some embodiments, the length L₂ of thesecond retention member 27110 can be between 1 mm and 4 mm. In someembodiments, the length L₂ of the second retention member 27110 can beapproximately 2 mm.

In some embodiments, the height H₃ of the support member 27102 can bebetween 6 mm and 16 mm. In some embodiments, the height H₃ of thesupport member 27102 can be approximately 8 mm. In some embodiments, theheight H₁ of the first retention member 27112 can be between 14 mm and32 mm. In some embodiments, the height H₁ of the first retention member27112 can be approximately 18 mm. Similarly, in some embodiments, theheight H₂ of the second retention member 27110 can be between 14 mm and32 mm. In some embodiments, the height H₂ of the second retention member27110 can be approximately 18 mm. Although the height H₁ and the heightH₂ are shown as being substantially equal, in other embodiments, theheight H₁ of the first retention member 27112 can be different than theheight H₂ of the second retention member 27110. Similarly, although thefirst retention member 27112 and the second retention member 27110 areshown as being positioned symmetrically about the lateral axis L_(L)when in their respective second positions (see FIG. 152), in someembodiments, the first retention member 27112 and/or the secondretention member 27110 can be positioned asymmetrically about thelateral axis L_(L) when in their respective second positions.

Although the first retention member 27112 and the second retentionmember 27110 are shown as being coupled to and disposed outside of thesupport member 27102, in some embodiments, the first retention member27112 and/or the second retention member 27110 can be arranged such thatat least a portion thereof is disposed within the support member 27102.For example, in some embodiments, a support member can define an openingin which a portion of a first retention member and/or a second retentionmember is disposed. In such embodiments, the opening of the supportmember can be, for example, a slot at an end portion of the supportmember configured to receive a portion of the first retention memberand/or the second retention member. In this manner, the first retentionmember and/or the second retention member can translate within the slotbetween a first position and a second position, as described above. Forexample, in some embodiments, an end portion of a retention member canbe disposed within the support member (e.g., within the slot defined bythe support member) when the retention member is in the first position.The end portion of the retention member can be disposed outside of thesupport member when the retention member is in the second position.

Although the implant 27100 is shown and described above as being rotatedrelative to the adjacent spinous processes SP1 and SP2 approximatelyninety degrees into the third configuration, in some embodiments, animplant can be rotated any suitable amount to during insertion. Forexample, in some embodiments, an implant can be rotated between 45degrees and 135 degrees. In other embodiments, an implant can be rotatedbetween 5 degrees and 90 degrees. In yet other embodiments, an implantcan be rotated between 5 and 175 degrees. Similarly, in someembodiments, an implant can be rotated incrementally when a retentionmember is translated relative to a support member of the implant.

Although the implant 27100 is shown and described as including a firstretention member 27112 and a second retention member 27110, in otherembodiments and implant can include only one retention member. Forexample, FIGS. 153-156 are schematic illustrations of an implant 27200according to an embodiment of the invention in a first configuration, asecond configuration, a third configuration and a fourth configuration,respectively. The implant 27200 includes a support member 27202 and aretention member 27212. The support member 27202 has a first end portion27206, a second end portion 27204 and an outer surface 27216. Thesupport member 27202 is tapered such that a size of the first endportion 27206 (e.g., the height H₁ as shown in FIG. 156) is less than asize of the second end portion 27204 (e.g., the height H₂ as shown inFIG. 156). In this manner, the outer surface 27216 of the support member27202 includes a tapered portion 27217. As shown in FIGS. 155 and 156,at least a portion of the outer surface 27216 is configured to bedisposed between a first spinous process SP1 and a second spinousprocess SP2.

The retention member 27212 has a first end portion 27230, a second endportion 27232 and defines a longitudinal axis L_(A). The first endportion 27230 of the retention member 27212 has an inner surface 27236and an outer surface 27237 opposite the inner surface 27236. Similarly,the second end portion 27232 of the retention member 27212 has an innersurface 27238 and an outer surface 27239 opposite the inner surface27238. Although the inner surface 27236 of the first end portion 27230and the inner surface 27238 of the second end portion 27232 are shown asforming a continuous, co-planar surface, in other embodiments, the innersurface 27236 of the first end portion 27230 can be discontinuous or ina plane different than the inner surface 27238 of the second end portion27232. Similarly, in some embodiments, the outer surface 27236 of thefirst end portion 27230 can be discontinuous or in a plane differentthan the outer surface 27238 of the second end portion 27232.

The retention member 27212 is slidably coupled to the first end portion27206 of the support member 27202. As indicated by the arrow RR in FIG.153, the retention member 27212 can translate along its longitudinalaxis L_(A) between a first position (FIGS. 153-155) and a secondposition (FIG. 156). When the retention member 27212 is in the firstposition, the first end portion 27230 is spaced apart from the supportmember 27202 and the second end portion 27232 is adjacent the first endportion 27206 of the support member 27202. Moreover, as described inmore detail herein, when the retention member 27212 is in the firstposition, the first end portion 27230 can contact and/or engage thefirst spinous process SP1 (either directly or indirectly through itssurrounding tissue) to limit lateral movement of the support member27202 along the lateral axis L_(L) and relative to the adjacent spinousprocesses SP1 and SP2. When the retention member 27212 is in the secondposition, the first end portion 27230 is spaced apart from the supportmember 27202 and the second end portion 27232 is spaced apart from thesupport member 27202. Moreover, as described in more detail herein, whenthe retention member 27212 is in the second position, the first endportion 27230 can contact and/or engage the first spinous process SP1(either directly or indirectly through its surrounding tissue) and thesecond end portion 27232 can be contact and/or engage the second spinousprocess SP2 (either directly or indirectly through its surroundingtissue). In this manner, when the retention member 27212 is in itssecond position, the retention member 27212 can limit lateral movementof the support member 27202 along the lateral axis L_(L) and relative tothe adjacent spinous processes SP1 and SP2.

In use, the implant 27200 can be inserted percutaneously along a lateralaccess passageway, as shown by the arrow RR in FIG. 153. As shown inFIG. 153, during insertion, the implant 27200 is placed in a firstconfiguration in which the retention member 27212 is in the firstposition and the longitudinal axis L_(A) of the retention member 27212is substantially parallel to the lateral axis L_(L). As described above,the implant 27200 is sized such that the implant 27200 can be disposedbetween the first spinous process SP1 and the second spinous process SP2when the implant is in the first configuration. In other embodiments,the implant 27200 can be sized such that the implant 27200 can distractthe adjacent spinous processes SP1 and SP2 during insertion.

When the implant 27200 is between the first spinous process SP1 and thesecond spinous process SP2, the implant 27200 can be rotated into thesecond configuration. As shown by the arrow SS in FIG. 154, the implant27200 can be rotated relative to the adjacent spinous processes SP1 andSP2 about an axis substantially normal to a mid-line axis L_(M) definedby the spinal column. The diagonal dimension D across the support member27202 and including a portion of the retention member 27212 is such thatthe implant 27200 can be disposed between the first spinous process SP1and the second spinous process SP2 when the implant is in the secondconfiguration. Said another way, the diagonal dimension D is sized suchthat the implant 27200 can be rotated as shown in FIG. 154.

As shown in FIG. 155, the implant 27200 can be rotated relative to theadjacent spinous processes SP1 and SP2 approximately ninety degrees intothe third configuration. When the implant 27200 is in the thirdconfiguration, the retention member 27212 is in its first position andthe longitudinal axis L_(A) of the retention member 27212 issubstantially parallel to the mid-line axis L_(M). Additionally, whenthe implant 27200 is in the third configuration, the inner surface 27236of the first end portion 27230 of the retention member 27212 can contactand/or engage the first spinous process SP1, either directly or throughsurrounding tissue. Said another way, when the implant 27200 is in thethird configuration, the inner surface 27236 of the first end portion27230 of the retention member 27212 is between the outer surface 27237of the first end portion 27230 of the retention member 27212 and thefirst spinous process SP1.

Moreover, when the implant 27200 is in the third configuration, thetapered portion 27217 of the outer surface 27216 of the support member27202 is adjacent the first spinous process SP1 and/or the secondspinous process SP2. In some embodiments, the tapered portion 27217 ofthe outer surface 27216 can substantially contact a portion of the firstspinous process SP1 and/or the second spinous process SP2 (eitherdirectly or indirectly through surrounding tissue) when the implant27200 is in the third configuration.

After the implant 27200 is placed in the third configuration, theretention member 27212 can be moved along its longitudinal axis L_(A)from the first position to the second position, as indicated by thearrow TT in FIG. 156. Said another way, the retention member 27212 canbe moved from the first position to the second position along an axissubstantially parallel to the mid-line axis L_(M). In this manner, theimplant can be placed into the fourth configuration, as shown in FIG.156.

When the implant 27200 is in the fourth configuration, the first endportion 27230 of the retention member 27212 is spaced apart from thesupport member 27202 and the second end portion 27232 of the retentionmember 27212 is spaced apart from the support member 27202. Moreover,when the implant 27200 is in the fourth configuration, the first endportion 27230 can contact and/or engage the first spinous process SP1and the second end portion 27232 can contact and/or engage the secondspinous process SP2. Said another way, when the implant 27200 is in thefourth configuration, the inner surface 27236 of the first end portion27230 of the retention member 27212 is between the outer surface 27237of the first end portion 27230 of the retention member 27212 and thefirst spinous process SP1. Similarly, the inner surface 27238 of thesecond end portion 27232 of the retention member 27212 is between theouter surface 27239 of the second end portion 27232 of the retentionmember 27212 and the second spinous process SP2. Additionally, when theimplant 27200 is in the fourth configuration, the tapered portion 27217of the outer surface 27216 remains between the first spinous process SP1and the second spinous process SP2. In this manner, when the implant27200 is in the fourth configuration, the retention member 27212 and/orthe tapered portion 27217 can limit lateral movement of the supportmember 27202 along the lateral axis L_(L) and relative to the adjacentspinous processes SP1 and SP2.

Although the support member 27206 is shown and described as beingasymmetrically tapered, in other embodiments, a support member can besymmetrically tapered. Said another way, although the portion of theouter surface 27216 adjacent the first spinous process SP1 (see FIGS.155 and 156) is shown as having a different amount of taper than thetapered portion 27217, in other embodiments, the portion of the supportmember adjacent the first spinous process SP1 can have the same taper asthe portion of the support member adjacent the second spinous processSP2.

Although the support member 27206 is shown and described as beingtapered linearly, in other embodiments, a support member can have acurved taper. Similarly, in some embodiments, an end portion of aretention member can be tapered. For example, in some embodiments an endportion of a retention member can include a pointed tip such that theimplant can define its own access passageway when inserted into thebody.

FIG. 157 is a flow chart illustrating a method 27300 according to anembodiment of the invention. The method includes inserting at least aportion of an implant between a first spinous process and a secondspinous process, 27304. The implant includes a support member and aretention member movably coupled to the support member. The implant canbe any suitable implant of the types shown and described above, such asfor example, the implant 27100.

In some embodiments, the inserting can include inserting the implantpercutaneously via a lateral access path. In some embodiments, theinserting can include positioning the implant such that a longitudinalaxis of the retention member is substantially parallel to a lateral axisdefined between the spinous processes. In some embodiments, the implantcan be inserted using a curved tool and/or a guide member, as describedherein. In some embodiments, the method can include optionallydistracting the adjacent spinous processes before the disposing, 27302.

The implant is then rotated relative to the first spinous process andthe second spinous process about an axis substantially normal to amid-line axis defined by a spinal column, 27306. In some embodiments,for example, the implant is rotated approximately ninety degreesrelative to the first spinous process and the second spinous process. Insome embodiments, for example, the implant is rotated such that an innersurface of an end portion of the retention member is between an outersurface of the end portion of the retention member and the first spinousprocess.

The retention member is translated relative to the support member,27308. In some embodiments, the retention member is translated relativeto the support member in a direction substantially parallel to themid-line axis defined by a spinal column. In some embodiments, theretention member is translated relative to the support member along thelongitudinal axis of the retention member. In some embodiments, theretention member is translated such that an inner surface of a secondend portion of the retention member is between an outer surface of thesecond end portion of the retention member and the second spinousprocess.

In some embodiments, the method can include optionally maintaining aposition of the retention member relative to the support member, 27310.The position of the retention member can be maintained, for example, bymoving a locking member such that a portion of the locking member isreceived within a recess defined by the support member and/or theretention member, as described above.

FIG. 158 is a flow chart illustrating a method 27400 according to anembodiment of the invention. The method includes inserting an implanthaving a first member, a second member and a third member such that atleast a portion of the first member is disposed between a first spinousprocess and a second spinous process, 27404. The implant can be anysuitable implant of the types shown and described above, such as forexample, the implant 27100.

In some embodiments, the inserting can include inserting the implantpercutaneously via a lateral access path. In some embodiments, theinserting can include positioning the implant such that a longitudinalaxis of the retention member is substantially parallel to a lateral axisdefined between the spinous processes. In some embodiments, the implantcan be inserted using a curved tool and/or a guide member, as describedherein. In some embodiments, the method can include optionallydistracting the adjacent spinous processes before the disposing, 27402.

The implant is then rotated relative to the first spinous process andthe second spinous process such that an inner surface the second memberis between an outer surface the second member and the first spinousprocess and an inner surface of the third member is between an outersurface of the third member and the second spinous process, 27406. Insome embodiments, for example, the implant is rotated about an axissubstantially normal to a mid-line axis defined by a spinal column. Insome embodiments, for example, the implant is rotated approximatelyninety degrees relative to the first spinous process and the secondspinous process.

The second member is translated relative to the first member, 27408. Insome embodiments, the second member is translated along a longitudinalaxis of the second member substantially parallel to the mid-line axisdefined by a spinal column. In some embodiments, the second member istranslated such that an inner surface of the second member is between anouter surface of the second member and the second spinous process.

In some embodiments, the method optionally includes translating thethird member relative to the first member, 27410. In some embodiments,the third member is translated along a longitudinal axis of the thirdmember substantially parallel to the mid-line axis. In some embodiments,the third member is translated such that an inner surface of the thirdmember is between an outer surface of the third member and the firstspinous process.

In some embodiments, the method can include optionally maintaining aposition of the second member and/or the third member relative to thesupport member, 27412. The position of the second member and/or thethird member can be maintained by a locking mechanism, as describedabove.

The various implants, deployment/insertion tools, and guide membersdescribed herein can be constructed with various biocompatible materialssuch as, for example, titanium, titanium alloyed, surgical steel,biocompatible metal alloys, stainless steel, plastic,polyetheretherketone (PEEK), carbon fiber, ultra-high molecular weight(UHMW) polyethylene, biocompatible polymeric materials, etc. Thematerial of a central portion of the implant can have, for example, acompressive strength similar to or higher than that of bone. In oneembodiment, the central portion of the implant, which is placed betweenthe two adjacent spinous processes, is configured with a material havingan elastic modulus higher than the elastic modulus of the bone, whichforms the spinous processes. In another embodiment, the central portionof the implant is configured with a material having a higher elasticmodulus than the materials used to configure the distal and proximalportions of the implant. For example, the central portion of the implantmay have an elastic modulus higher than bone, while the proximal anddistal portions have a lower elastic modulus than bone. In yet anotherembodiment, where the implant is configured with an outer shell and aninner core. The outer shell can be configured with material having ahigher elastic modulus than the inner core (e.g., outer shell is madewith titanium alloyed, while the inner core is made with a polymericmaterial). Alternatively, the outer shell can be configured with amaterial having a lower elastic modulus than the inner core (e.g., theouter shell is made with a polymeric material while the inner core ismade with a titanium alloyed material).

While various embodiments of the invention have been described above, itshould be understood that they have been presented by way of exampleonly, and not limitation. Where methods and steps described aboveindicate certain events occurring in certain order, those of ordinaryskill in the art having the benefit of this disclosure would recognizethat the ordering of certain steps may be modified and that suchmodifications are in accordance with the variations of the invention.Additionally, certain of the steps may be performed concurrently in aparallel process when possible, as well as performed sequentially asdescribed above. Thus, the breadth and scope of the invention should notbe limited by any of the above-described embodiments, but should bedefined only in accordance with the following claims and theirequivalents. While the invention has been particularly shown anddescribed with reference to specific embodiments thereof, it will beunderstood that various changes in form and details may be made.

For example, although the embodiments above are primarily described asbeing spinal implants configured to be positioned between adjacentspinous processes, in alternative embodiments, the implants areconfigured to be positioned adjacent any bone, tissue or other bodilystructure where it is desirable to maintain spacing while preventingaxial or longitudinal movement of the implant.

Although the medical devices are shown and described as including animplant and/or a deployment tool, in some embodiments a kit can includeany number of implants and/or any number of deployment tools and/or anynumber of guide members as described above. For example, a kit caninclude an implant and two deployment tools, one deployment toolconfigured to be used to move the implant from a collapsed configurationto an expanded configuration, and another deployment tool configured tobe used to move the implant from the expanded configuration to thecollapsed configuration. Alternatively, a kit can include a singledeployment tool have multiple engaging portions as described herein,that can be releasably coupled to an elongate member of a deploymenttool. For example, one type or style of engaging portion can be used tomove the implant from a collapsed configuration to an expandedconfiguration, and another type or style of engaging portion can be usedto move the implant from the expanded configuration to the collapsedconfiguration. The kit can include engaging portions having one of avariety of different shapes and sizes, such that a user can select aparticular engaging portion(s) for use in a particular application. Inanother example, a kit can include more than one guide member, eachhaving a different length to accommodate different needs and/or uses.

Similarly, although various embodiments have been described as havingparticular features and/or combinations of components, other embodimentsare possible having a combination of any features and/or components fromany of embodiments as discussed above. For example, one such embodimentincludes an implant having a locking mechanism of the type shown anddescribed above with reference to FIGS. 95-99 and two retention membersconfigured to rotate about an axis of rotation substantially normal to alongitudinal axis of the implant, as shown and described above withreference to FIGS. 124-127.

Although various implants have been shown and described above as havinga first configuration and a second configuration, in some embodiments,an implant can include three or more configurations. For example, insome embodiments, an implant can have a first configuration, in whichthe implant can be inserted between the spinous processes unimpeded by aretention member of the implant, a second configuration, in whichlateral movement of the implant is limited by the retention member and athird configuration in which the implant can move in one lateraldirection, but not the other.

Similarly, in some embodiments, a deployment tool, an expansion deviceand/or an insertion tool can be configured to perform any combination offunctions described herein. For example, in some embodiments, adeployment tool, an expansion devices and/or an insertion tool can beconfigured to insert a spinal implant into a body, move a spinal implantbetween a retracted configuration and an expanded configuration within abody, reposition a spinal implant within the body and/or remove a spinalimplant within the body. In some embodiments, a deployment tool, anexpansion device and/or an insertion tool can be configured to performonly a single function, such as, for example, removing a spinal implantfrom body. In other embodiments, a kit can include a deployment tool, anexpansion device and/or an insertion tool along with various implementsso that the deployment tool, expansion device and/or insertion tool canbe re-configured to perform any combination of functions describedherein.

1. An apparatus comprising: a first member having a first surface and asecond surface, the second surface offset from a longitudinal axis ofthe first member by a non-zero angle, at least a portion of the firstsurface configured to engage a spinous process; and a second memberrotatably coupled to a distal end of the first member, the second memberconfigured to move relative to the first member between a first positionand a second position, at least a portion of a surface of the secondmember being disposed adjacent at least a portion of the second surfaceof the first member when the second member is in the first position, theportion of the surface of the second member being disposed apart fromthe portion of the second surface of the first member when the secondmember is in the second position, the portion of the surface of thesecond member configured to limit movement of the first member along thelongitudinal axis and relative to the spinous process when the secondmember is in the second position.
 2. The apparatus of claim 1, whereinthe first surface of the first member is substantially parallel to thelongitudinal axis of the first member.
 3. The apparatus of claim 1,wherein the surface of the second member is substantially parallel tothe second surface of the first member.
 4. The apparatus of claim 1,wherein the second surface of the first member is disposed at the distalend of the first member.
 5. The apparatus of claim 1, wherein thesurface of the second member is in contact with the portion of thesecond surface of the first member when the second member is in thefirst position.
 6. The apparatus of claim 1, wherein the portion of thesurface of the second member is configured to engage the spinous processto limit movement of the first member along the longitudinal axis andrelative to the spinous process.
 7. The apparatus of claim 1, whereinthe second member is configured to rotate relative to the first memberfrom the first position to the second position about an axissubstantially parallel to the longitudinal axis of the first member. 8.The apparatus of claim 1, wherein: the spinous process is a firstspinous process; the first member and the second member are configuredto be inserted percutaneously such that the portion of the first surfaceof the first member is between the first spinous process and a secondspinous process; and the second member is configured to move from thefirst position to the second position after the at least the portion ofthe first member is disposed between the first spinous process and thesecond spinous process.
 9. The apparatus of claim 1, wherein: the secondsurface of the first member has an area; and the surface of the secondmember has an area, the area of the surface of the second member beingwithin the area of the second surface of the first member when projectedon a plane substantially normal to the longitudinal axis and when thesecond member is in the first position, a portion of the area of thesurface of the second member being outside of the area of the secondsurface of the first member when projected on the plane substantiallynormal to the longitudinal axis and when the second member is in thesecond position.
 10. The apparatus of claim 1, wherein a portion of thesurface of the second member and a portion of the first surface of thefirst member collectively form a portion of a saddle configured toreceive a portion of the spinous process when the second member is inthe second position.
 11. The apparatus of claim 1, wherein the surfaceof the second member is a first surface, the second member including asecond surface substantially parallel to the first surface of the firstmember, the apparatus further comprising: a locking member disposedwithin the first member and configured to engage the first surface ofthe second member when the second member is in the first position, atleast a portion of the locking member disposed outside of the firstmember and configured to engage the second surface of the second memberwhen the second member is in the second position; and a biasing memberdisposed within the first member, the biasing member configured to biasthe locking member such that the portion of the locking member isdisposed outside of the first member.
 12. The apparatus of claim 1,wherein: the surface of the second member is a first surface; and thesecond member includes a second surface having a curved shapeasymmetrical about the longitudinal axis.
 13. The apparatus of claim 1,wherein: the surface of the second member is a first surface; and thesecond member includes a second surface configured to dilate a bodilytissue.
 14. The apparatus of claim 1, wherein: the surface of the secondmember is a first surface; and the second member includes a secondsurface configured to distract a space between the spinous process andan adjacent spinous process.
 15. An apparatus, comprising: a supportmember having at least a portion configured to be disposed between afirst spinous process and a second spinous process; and a retentionmember movably coupled to an end portion of the support member, theretention member configured to displace a bodily tissue, the retentionmember configured to move relative to the support member from a firstposition to a second position, the retention member configured to limitmovement of the support member along a longitudinal axis of the supportmember and relative to the first spinous process and the second spinousprocess when in the second position.
 16. The apparatus of claim 15,wherein the retention member is configured to rotate about an axissubstantially parallel to a longitudinal axis of the support member. 17.The apparatus of claim 15, wherein: a portion of the retention member isdisposed within the support member when the retention member is in thefirst position; and the portion of the retention member is disposedoutside of the support member when the retention member is in the secondposition.
 18. The apparatus of claim 15, wherein: the end portion of thesupport member has a cross-sectional area normal to the longitudinalaxis of the support member; and the retention member has across-sectional area normal to the longitudinal axis of the supportmember, the cross-sectional area of the retention member being withinthe cross-sectional area of the end portion of the support member whenprojected on a plane substantially normal to the longitudinal axis andwhen the retention member is in the first position, a portion of thecross-sectional area of the retention member being outside of thecross-sectional area of the end portion of the support member whenprojected on the plane substantially normal to the longitudinal axis andwhen the retention member is in the second position.
 19. The apparatusof claim 15, wherein: the support member and the retention member areconfigured to be inserted between the first spinous process and thesecond spinous process percutaneously; and the retention member isconfigured to move from the first position to the second position afterthe support member is disposed between the first spinous process and thesecond spinous process.
 20. The apparatus of claim 15, wherein thesupport member and the retention member are configured to be insertedbetween the first spinous process and the second spinous processpercutaneously in a direction along the longitudinal axis of the supportmember.
 21. The apparatus of claim 15, wherein: the support member istapered such that a size of a distal end portion of the support memberalong an axis substantially normal to the longitudinal axis is less thana size of a proximal end portion of the support member along the axissubstantially normal to the longitudinal axis; and the retention memberis movably coupled to the distal end portion of the support member. 22.The apparatus of claim 15, wherein a portion of the retention member anda portion of the support member collectively form a portion of a saddleconfigured to receive a portion of the first spinous process when theretention member is in the second position.
 23. The apparatus of claim15, wherein the portion of the support member is configured to engagethe first spinous process and the second spinous process upon spinalextension.
 24. The apparatus of claim 15, wherein the retention memberis configured to repeatedly move between the first position and thesecond position.
 25. The apparatus of claim 15, wherein the retentionmember is a first retention member and the end portion of the supportmember is a distal end portion, the apparatus further comprising: asecond retention member movably coupled to a proximal end portion of thesupport member, the second retention member configured to rotaterelative to the support member from a first position to a secondposition about the axis substantially parallel to the longitudinal axisof the support member, the second retention member configured to limitmovement of the support member along the longitudinal axis and relativeto the first spinous process and the second spinous process when in thesecond position.
 26. The apparatus of claim 15, further comprising alocking member configured to releasably maintain the retention member inthe second position.
 27. The apparatus of claim 15, further comprising:a locking member disposed within the support member and configured toengage a first surface of the retention member when the retention memberis in the first position such that the retention member is maintained inthe first position, at least a portion of the locking member disposedoutside of the support member and configured to engage a second surfaceof the retention member when the retention member is in the secondposition such that the retention member is maintained in the secondposition, the second surface different than the first surface.
 28. Theapparatus of claim 15, further comprising: a locking member disposedwithin the support member and configured to engage a first surface ofthe retention member when the retention member is in the first positionsuch that the retention member is maintained in the first position, atleast a portion of the locking member disposed outside of the supportmember and configured to engage a second surface of the retention memberwhen the retention member is in the second position such that theretention member is maintained in the second position, the secondsurface different than the first surface; and a biasing member disposedwithin the support member, the biasing member configured to bias thelocking member in a direction such that the at least the portion of thelocking member is disposed outside of the support member.
 29. Theapparatus of claim 15, wherein the retention member has an outer surfacethat is curved asymmetrically about the longitudinal axis.
 30. Theapparatus of claim 15, wherein the retention member has a tapered endportion configured to dilate the bodily tissue.
 31. the apparatus ofclaim 15, wherein the retention member is configured to distract a spacebetween the first spinous process and the second spinous process.
 32. Anapparatus comprising: a support member having at least a portionconfigured to engage adjacent spinous processes, a distal end of thesupport member having a cross-sectional area normal to a longitudinalaxis of the support member; and a retention member rotatably coupled tothe distal end of the support member, the retention member having across-sectional area normal to the longitudinal axis of the supportmember, the retention member configured to rotate relative to thesupport member about an axis substantially parallel to the longitudinalaxis of the support member from a first position to a second position,the retention member configured to limit movement of the support memberalong the longitudinal axis and relative to the first spinous processand the second spinous process when in the second position, thecross-sectional area of the retention member being within thecross-sectional area of the distal end of the support member whenprojected on a plane substantially normal to the longitudinal axis andwhen the retention member is in the first position, a portion of thecross-sectional area of the retention member being outside of thecross-sectional area of the distal end of the support member whenprojected on the plane substantially normal to the longitudinal axis andwhen the retention member is in the second position.
 33. The apparatusof claim 32, wherein: the support member and the retention member areconfigured to be inserted between the first spinous process and thesecond spinous process percutaneously; and the retention member isconfigured to rotate from the first position to the second positionafter the support member is disposed between the first spinous processand the second spinous process.
 34. The apparatus of claim 32, whereinthe support member is tapered such that a size of the distal end portionof the support member along an axis substantially normal to thelongitudinal axis is less than a size of a proximal end portion of thesupport member along the axis substantially normal to the longitudinalaxis.
 35. The apparatus of claim 32, wherein a portion of the retentionmember and a portion of the support member collectively form a portionof a saddle configured to receive the first spinous process when theretention member is in the second position.
 36. The apparatus of claim32, wherein: a proximal end of the retention member is coupled to thedistal end of the support member; and the cross-sectional area of theretention member is coincident with the proximal end of the retentionmember.
 37. The apparatus of claim 32, wherein the retention member isconfigured to repeatedly move between the first position and the secondposition.
 38. The apparatus of claim 32, wherein the retention member isa first retention member, the apparatus further comprising: a secondretention member rotatably coupled to a proximal end portion of thesupport member, the second retention member configured to rotaterelative to the support member from a first position to a secondposition about an axis substantially parallel to the longitudinal axisof the support member, the second retention member configured to limitmovement of the support member along the longitudinal axis and relativeto the first spinous process and the second spinous process when in thesecond position.
 39. The apparatus of claim 32, further comprising alocking member configured to reversibly maintain the retention member inthe second position.
 40. The apparatus of claim 32, further comprising:a locking member disposed within the support member and configured toengage a proximal surface of the retention member when the retentionmember is in the first position such that the retention member ismaintained in the first position, at least a portion of the lockingmember disposed outside of the support member and configured to engagean outer surface of the retention member when the retention member is inthe second position such that the retention member is maintained in thesecond position; and a biasing member disposed within the supportmember, the biasing member configured to bias the locking member in adirection such that the at least the portion of the locking member isdisposed outside of the support member.
 41. An apparatus comprising: asupport member having at least a portion configured to engage adjacentspinous processes, a distal end of the support member having a firstdimension along a first axis substantially normal to a longitudinal axisof the support member and a second dimension along a second axis, thesecond axis being substantially normal to the longitudinal axis and thefirst axis, the second dimension greater than the first dimension; and aretention member movably coupled to the distal end of the supportmember, the retention member configured to displace a bodily tissue, theretention member configured to move relative to the support member froma first position to a second position, the retention member having afirst dimension along the first axis and a second dimension along thesecond axis, the first dimension of the retention member being greaterthan the second dimension of the support member and no greater than thefirst dimension of the support member, the second dimension of theretention member being no greater than the second dimension of thesupport member.
 42. The apparatus of claim 41, wherein the retentionmember is configured to rotate relative to the support member from thefirst position to the second position about an axis substantiallyparallel to the longitudinal axis of the support member.
 43. Theapparatus of claim 41, wherein: the first dimension of the retentionmember is aligned with the first dimension of the support member whenthe retention member is in the first position; and the first dimensionof the retention member is aligned with the second dimension of thesupport member when the retention member is in the second position. 44.The apparatus of claim 41, wherein: the first dimension of the retentionmember is substantially equal to the first dimension of the supportmember; and the second dimension of the retention member issubstantially equal to the second dimension of the support member. 45.The apparatus of claim 41, wherein the retention member is configured torepeatedly move between the first position and the second position. 46.The apparatus of claim 41, wherein the retention member is a firstretention member, the apparatus further comprising: a second retentionmember movably coupled to a proximal end portion of the support member,the second retention member configured to rotate relative to the supportmember from a first position to a second position about an axissubstantially parallel to the longitudinal axis of the support member,the second retention member configured to limit movement of the supportmember along the longitudinal axis and relative to the first spinousprocess and the second spinous process when in the second position. 47.The apparatus of claim 41, further comprising: a locking member disposedwithin the support member and configured to engage a proximal surface ofthe retention member when the retention member is in the first positionsuch that the retention member is maintained in the first position, atleast a portion of the locking member disposed outside of the supportmember and configured to engage an outer surface of the retention memberwhen the retention member is in the second position such that theretention member is maintained in the second position; and a biasingmember disposed within the support member, the biasing member configuredto bias the locking member in a direction such that the at least theportion of the locking member is disposed outside of the support member.48. The apparatus of claim 41, wherein the retention member has atapered end portion configured to dilate the bodily tissue.
 49. theapparatus of claim 41, wherein the retention member is configured todistract a space between the first spinous process and the secondspinous process.
 50. An apparatus comprising: a support memberconfigured to be disposed between a first spinous process and a secondspinous process; a retention member movably coupled to a distal end ofthe support member, the retention member configured to move from a firstposition to a second position to limit movement of the support memberalong a longitudinal axis and relative to the first spinous process andthe second spinous process; and a locking member disposed within thesupport member and configured to engage a first surface of the retentionmember when the retention member is in the first position such that theretention member is maintained in the first position, at least a portionof the locking member disposed outside of the support member andconfigured to engage a second surface of the retention member when theretention member is in the second position such that the retentionmember is maintained in the second position, the second surfacedifferent than the first surface.
 51. The apparatus of claim 50, whereinthe retention member is configured to rotate relative to the supportmember from the first position to the second position about an axissubstantially parallel to the longitudinal axis of the support member.52. The apparatus of claim 50, wherein: the support member and theretention member are configured to be inserted between the first spinousprocess and the second spinous process percutaneously; and the retentionmember is configured to move from the first position to the secondposition after the support member is disposed between the first spinousprocess and the second spinous process.
 53. The apparatus of claim 50,wherein: the distal end of the support member has a cross-sectional areanormal to a longitudinal axis of the support member; and the retentionmember has a cross-sectional area normal to the longitudinal axis of thesupport member, the cross-sectional area of the retention member beingwithin the cross-sectional area of the distal end of the support memberwhen projected on a plane substantially normal to the longitudinal axisand when the retention member is in the first position, a portion of thecross-sectional area of the retention member being outside of thecross-sectional area of the distal end of the support member whenprojected on the plane substantially normal to the longitudinal axis andwhen the retention member is in the second position.
 54. The apparatusof claim 50, wherein the retention member is configured to repeatedlymove between the first position and the second position.
 55. Theapparatus of claim 50, wherein: the first surface of the retentionmember includes a recessed portion configured to receive a first portionof the locking member when the retention member is in the firstposition; and the second surface of the retention member includes arecessed portion configured to receive a second portion of the lockingmember when the retention member is in the second position.
 56. Theapparatus of claim 50, wherein the retention member is a first retentionmember, the apparatus further comprising: a second retention membermovably coupled to a proximal end of the support member, the secondretention member configured to rotate relative to the support memberfrom a first position to a second position about an axis substantiallyparallel to a longitudinal axis of the support member, the secondretention member configured to limit movement of the support memberalong the longitudinal axis and relative to the first spinous processand the second spinous process when in the second position.
 57. Theapparatus of claim 50, further comprising: a biasing member disposedwithin the support member, the biasing member configured to bias thelocking member in a direction such that the at least the portion of thelocking member is disposed outside of the support member.
 58. A methodcomprising: disposing at least a portion of an implant between adjacentspinous processes, the implant including a support member and aretention member movably coupled to the support member; rotating theretention member from a first position to a second position such thatthe retention member retains a portion of the implant between theadjacent spinous processes; and locking reversibly the retention memberin the second position.
 59. The method of claim 58, wherein thedisposing includes inserting the implant percutaneously via a lateralaccess path including a portion at the sides of the adjacent spinousprocesses.
 60. The method of claim 58, wherein: the retention member isdisposed within the support member when in the first position; and aportion of the retention member is disposed outside of the supportmember when in the second position.
 61. The method of claim 58, whereinthe rotating includes rotating the retention member about an axissubstantially parallel to a longitudinal axis of the support member. 62.The method of claim 58, wherein: an end portion of the support memberhas a cross-sectional area normal to the longitudinal axis of thesupport member; the retention member has a cross-sectional area normalto the longitudinal axis of the support member, the cross-sectional areaof the retention member being within the cross-sectional area of thedistal end of the support member projected on a plane substantiallynormal to the longitudinal axis and when the retention member is in thefirst position; and the rotating includes rotating the retention membersuch that a portion of the cross-sectional area of the retention memberis outside of the cross-sectional area of the distal end of the supportmember when projected on the plane substantially normal to thelongitudinal axis.
 63. The method of claim 58, wherein the disposingincludes disposing the implant such that a portion of the retentionmember distracts a space between the adjacent spinous processes.
 64. Themethod of claim 58, further comprising distracting a space between theadjacent spinous processes before the disposing.
 65. An apparatus,comprising: a support member having at least a portion configured to bedisposed between a first spinous process and a second spinous process; afirst retention member movably coupled to a first end portion of thesupport member; and a second retention member movably coupled to asecond end portion of the support member, the second retention membercoupled to the first retention member such that the first retentionmember and the second retention member are configured to collectivelymove relative to the support member from a first position to a secondposition, the first retention member and the second retention memberconfigured to limit movement of the support member relative to the firstspinous process and the second spinous process when in the secondposition.
 66. The apparatus of claim 65, wherein the first retentionmember and the second retention member are configured to collectivelyrotate relative to the support member from the first position to thesecond position.
 67. The apparatus of claim 65, wherein the firstretention member and the second retention member are configured tocollectively rotate relative to the support member about an axissubstantially parallel to the longitudinal axis of the support member.68. The apparatus of claim 65, wherein the first end portion of thesupport member has a cross-sectional area normal to the longitudinalaxis of the support member; the first retention member has across-sectional area normal to the longitudinal axis of the supportmember; the second end portion of the support member has across-sectional area normal to the longitudinal axis of the supportmember; and the second retention member has a cross-sectional areanormal to the longitudinal axis of the support member, thecross-sectional area of the first retention member being within thecross-sectional area of the first end portion of the support member whenprojected on a plane substantially normal to the longitudinal axis andwhen the first retention member is in the first position, a portion ofthe cross-sectional area of the first retention member being outside ofthe cross-sectional area of the first end portion of the support memberwhen projected on the plane substantially normal to the longitudinalaxis and when the first retention member is in the second position, thecross-sectional area of the second retention member being within thecross-sectional area of the second end portion of the support memberwhen projected on a plane substantially normal to the longitudinal axisand when the second retention member is in the first position, a portionof the cross-sectional area of the second retention member being outsideof the cross-sectional area of the second end portion of the supportmember when projected on the plane substantially normal to thelongitudinal axis and when the second retention member is in the secondposition.
 69. The apparatus of claim 65, wherein: the support member,the first retention member and the second retention member areconfigured to be inserted between the first spinous process and thesecond spinous process percutaneously; and the first retention memberand the second retention member are configured to collectively moverelative to the support member from the first position to the secondposition after the support member is disposed between the first spinousprocess and the second spinous process.
 70. The apparatus of claim 65,wherein a portion of the support member, a portion of the firstretention member and a portion of the second retention membercollectively form a portion of a saddle configured to receive a portionof the first spinous process when the first retention member and thesecond retention member are in the second position.
 71. The apparatus ofclaim 65, wherein the first retention member and the second retentionmember are configured to repeatedly move between the first position andthe second position.
 72. The apparatus of claim 65, further comprising alocking member configured to releasably maintain the first retentionmember and the second retention member in the second position.